Final Attempt - Misfire Issue

[sk47]

would really appreciate if only experienced members that have dealt with this issue / have the knowledge would comment to not stray away from the issue here.

Hello; Since I do not have the exact answer allow me to tell a story or two. You should feel free to stop reading at this point.
I live near a small college with a rental house next door. The current student has turned out to be friendly. I offered to allow her to take shelter in my basement if/when a tornado warning is in effect. I have done so for other neighbors. I wind up going to the basement four or five times a year. So far, no tornado has hit. A couple hit within a mile or ten.
So last year got a warning. I called the neighbor and went to the basement. She did not show up. Just a heavy storm with light wind damage.
Next few days she tells me my call made her nervous and please would I only call if I knew for sure it was a tornado. Since I do not know how to know for sure I do not call anymore.

Back some years ago I was trying to help a friend with a poor running car. It had points. I started to remove the distributor cap to check the points, rotor button and cap. He assured me a mechanic had already changed all those parts. So i wasted a few hours on other stuff and did not get to run right. Next time I saw him I was told it was the points. Lesson learned. Do the basics and check for yourself.

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[gilbenja]

Sounds to me like you need a track day, which is probably the easiest way to stress test the hardware and find a sometimes faulty component! Worked for me

I agree on replacing the crank sensor… it’s cheap and easy. Same goes for the other diagnostic steps @Cobra Jet pointed out.

To me, this screams a faulty connection at a connector or a weak connection in a wiring harness somewhere. When one of my VCt solenoids was about to go out (I lost all 4 at one point or another), or the wiring pigtail connection between the VCT and main harness was about to go out, I would get random misfires until something fully failed.

Since the issue is presenting under heavy load when the engine is torquing in the engine bay, especially when going uphill when gravity pulling at the harness in a slightly different way, maybe that points to something in the wiring? I’ve had some limited success with using the misfire counter page on a code reader while using my hand to shake the wiring harness and all connections in the engine bay (preferably doing it while the engine is under load.). If you’re getting misfires to a particular cylinder, then your issue is in the wire to a specific plug, coil, injector, or the wiring to each. If you’re seeing misfires in one bank of the engine, I’d suspect the VCT system or cam position sensor. If the misfires are coming from everywhere randomly, I’d suspect a vacuum/air leak, or sensor (such as crank or maybe MAF). At any rate, if you don’t have a good OBD reader, you probably need one. You really need to play the long run game of trying to catch the engine misfiring in the act… which means lots of time hooked up to a code reader while using lots of gasoline.

Maintenance issues like this suck, but unless you get lucky with a sensor replacement or a loose wiring, you’re not going to find a magic bullet fix on the forum. Sometimes a car is worth the frustration of chasing down a gremlin… sometimes not. You started and ended the post with talking about selling the car. Sounds to me like you’re about to sell the car. . .

Best of luck (from a former mustang owner who couldn’t handle the frustration of a constantly breaking car.)

Are you half joking when saying this? My dad suggested that I just keep driving the car with the light on until something breaks. Since he doesn’t believe it to be an engine or transmission concern.

I’m going to have to save up or learn how to take out my transmission. I guess it’s a cheap fix for the part but the labor is what would be expensive.

 

[Inthehighdesert]

Or plan b is to take the car to someone that knows wtf they’re doing and fix it, as opposed to take a massive hit on vehicle that isn’t functioning properly. Funny part is, and not funny haha, is many on here have lots of experience with these cars. And I’d venture to say in a lot of cases even more then most techs at Ford dealerships. I’m not going to harp on the coil that a previous tech followed the misfunction to accompanying cylinder. But these parts, coil, crank trigger, etc. cost almost zero in the grand scheme of things and are certainly less then shuttling a car from tech to tech. These parts are simple swaps even for a newbie and inexperienced. Wish the op the best but at this point it’s to much analysis paralysis and not enough actual hands on.

The mechanic isnt saying the transmission is making noise he’s saying there are metal shavings in the transmission case and may be causing issues with a speed sensor inside the case.

Anyway if I were the OP and I could sell the car, I might. No fun with random problems and if your car isnt modded to all heck, why not get rid of it.

Fueling issues could be the case. fWIW when I had fuel issues it was pretty clear on a datalog that the injectors were going to 100% and that was enough to know the fuel pressure was low and the pump was going out.

OP needs to find a local mechanic he trysts because aint none of yall gonna diagnose it over the internet. Someone local has to figure it out for him.

 

[pilotgore]

Are you half joking when saying this? My dad suggested that I just keep driving the car with the light on until something breaks. Since he doesn’t believe it to be an engine or transmission concern.

I’m going to have to save up or learn how to take out my transmission. I guess it’s a cheap fix for the part but the labor is what would be expensive.

As others have said, fuel pressure readings seem like a smarter bet…. But yeah, a track day will absolutely help you find and destroy the weakest component on your car…

 

[Inthehighdesert]

Kind of like possibly having a valve issue in your heart and deciding to go run a marathon.

As others have said, fuel pressure readings seem like a smarter bet…. But yeah, a track day will absolutely help you find and destroy the weakest component on your car…

 

[pilotgore]

Kind of like possibly having a valve issue in your heart and deciding to go run a marathon.

Ha! I mean; if you don’t know which valve is bad, you’ll know 1 mile into the marathon. Mission accomplished!!

 

[Cobra Jet]

I’ll add again too, just because some Tech at a Ford Dealership says he’s worked on S550 GT350’s doesn’t mean he knows what he’s doing - which is 100% clear by his notes in that Ford work order…. And probably why there’s (6) other GT350’s sitting in that service center lot too… LMAO…. Now on a serious note, there ARE EXCELLENT Techs at some Ford Service Centers that know their shit and take the time to do what is right… so we can’t lump all Ford Techs into a shitpile, but many people at XYZ jobs today just want an easy way out to get to the next level or next job (more so when they’re working against book time like Service Centers at ANY vehicle Dealership).

Take it one step at a time and diagnose like we have given you the info to do so…. Taking it to multiple Shops and getting 3, 4, 10+ Techs telling you A, B, C, and D isn’t getting you anywhere…. It’s certainly not reducing the level of confusion and conflicting responses you’re getting after each Tech reviews the problem. I mean, the isn’t take it to 10 shops and then average out who may be right or better than the last or next.

Take one piece of advice here in just this thread alone, whether it’s Member A or Member B offering advice on testing fuel pressure or popping XYZ sensor off to physically look at it, or from Member C to do a wiggle test on a connector or harness, etc etc…. IMO, you’re going to get ahead faster doing it based on the advice you have been give here - than the next shop you drop the car off at… AND most importantly you will LEARN how to do your own diagnosis and even the repair itself, which is rewarding in many ways.

And you should have said to the Tech who made those notes that your trans wouldn’t have metal shavings in it if he didn’t grind 2nd or 3rd gear at who knows what speed/RPM….

 

[sk47]

Are you half joking when saying this? My dad suggested that I just keep driving the car with the light on until something breaks. Since he doesn’t believe it to be an engine or transmission concern.

I’m going to have to save up or learn how to take out my transmission. I guess it’s a cheap fix for the part but the labor is what would be expensive.

Hello; finally, a useful clue or two. I suspect you are young. I suspect you are not experienced working on cars. Neither condition is bad. All of us were young & inexperienced at some point.

The good portion of your situation is you have a vehicle worth fixing. May wind up being expensive but unlike so many average cars is not one to be discarded. You bought a car which fits in the category of a 1964 or 65 Pontiac GTO, A 1969 Camaro, a 1967 or 68 Mustang GT fastback. I do not know the MoPar models so well, but one guy has made a living restoring Dodge cars. He has a TV show. Graveyard Cars I think. Mark Worman. Spend what it takes to fix the car sort if you can raise the money.

If I have not mixed up your various threads with other members threads, I think you have considering selling the car as the frustration builds with this one. I have a request if you do sell the car. Please post the VIN on this site so fellow members can know the history.

I do not know your financial situation. I do not know how much you paid for the car. What i can guess about is you are on an expensive path with this car. I understand why you want some clear and distinct answer about the problem. Such would give an idea of the final cost before you dig deeper into the car.
My take from experience is even with mistakes & bad decisions it is less expensive to DIY a car than to pay someone else to do the work. Over time ownership costs seem to work out better and you wind up with skills and a ton of tools.
I would not have suggested the car you have to learn how to work on cars with, but you already have it.

learn how to take out my transmission. I guess it’s a cheap fix for the part but the labor is what would be expensive.

Hello; Yes, labor can be much more that parts cost. This is how DIY pays off. A transmission is like a complicated 3-D jigsaw puzzle. Might be a hard first timer job. Might require expensive special tools. I have opened up some manuals but not automatics. I did work in a small automatic transmission shop as a helper back when in college. Got OK at removing & installing but never tried to pull the guts of one.
But yes, go for it. You have little to lose if that one mechanic is correct and the transmission is " full of metal". A transmission actually full of metal is on the way to being junk. Here is a suggestion- check for yourself if the transmission has loose metal bits in it by draining the fluid. Not so complicated to do and a good DIY skill to have.

 

[CANTWN4LSN]

If you were in Texas I would suggest you take your car to HPP Racing by Dallas. I know they could 100% diagnose your issue. Find a shop that builds race cars. They will figure it out.

This. All you guys suggesting these wonderful, insightful, and erudite evaluations are great but probably beyond most of our abilities without experience, a shop manual, multiple trips to Harbor Freight, and a dedicated helper. What would be most helpful is if someone knew a shop near him in CA like this one in TX or if the guys in Dallas know someone in his location who after reading all these fine suggestions could agree and offer to evaluate and fix the car for him. Sounds like he just wants to get it fixed and drive it since it isn't a quick fix. Just a suggestion from a non-gear head.

 

[sk47]

This. All you guys suggesting these wonderful, insightful, and erudite evaluations are great but probably beyond most of our abilities without experience, a shop manual, multiple trips to Harbor Freight, and a dedicated helper. What would be most helpful is if someone knew a shop near him in CA like this one in TX or if the guys in Dallas know someone in his location who after reading all these fine suggestions could agree and offer to evaluate and fix the car for him. Sounds like he just wants to get it fixed and drive it since it isn't a quick fix. Just a suggestion from a non-gear head.

Hello; Here is the catch as I see it. To evaluate the posted problems from a distance requires "gear-heads" with hands on experience. Folks who are DIY oriented are naturally going to use personal experience. I suppose a good reason for learning how engines & transmissions work is to be somewhat informed when you do wind up with a car in a shop.
One advantage is the shop folks can tell if you know the ins & outs of systems which makes two things happen. One being they will not try to BS you like they might a novice. Another might be they realize you will know if noises are normal.

But I get many folks are not interested in knowing how things work. Some just want to pay for a car and drive it. Not a wrong way to be, just more expensive. Merely requires enough money. If very lucky to have an honest & competent shop.

I posted in the unofficial off topic about a shop in my area (Gatlinburg TN). A man left his Mach 1 in the shop in 2020 and paid some $25 K to the shop. He finally took the shop owner to court to get his car back. Not only was the paid for work not done the car was stripped of many parts originally already on the car.
I asked a question in that thread which I repeat. Is there any sort of listing or data base on this site or elsewhere we can go to and find honest or competent shops???? Preferably honest & competent together.

Going back to the first of several threads of the OP, we have been trying to help the OP wade thru reports of a few shops.

 

[Guusgeluk]

Believe it or not, i have had more or less the same issue, hesitation hill up during low rpm (load), serveral misfires, no codes.

Ford gave me this report in Dutch, basically saying “accept it, live with it”. A respectable tuner fixed the issue afterwards, had apparently to do something with environmental limitations. US version GT 2021, 10 speed, premium fuel.

 

[mt82#1fan]

Have you checked all of the clamps for the intake and cleaned the MAF sensor? I had similar code pop up at the track under heavy braking and it turned out under deceleration the intake tubing would compress as the motor rocked forward allowing a gap in the intake for un-metered air to get in and throw off the a/f ratios enough to trip a CEL. Good luck

 

[SnowFox]

Are you half joking when saying this? My dad suggested that I just keep driving the car with the light on until something breaks. Since he doesn’t believe it to be an engine or transmission concern.

I’m going to have to save up or learn how to take out my transmission. I guess it’s a cheap fix for the part but the labor is what would be expensive.

Sometimes, driving it till something breaks isn't a bad idea IF you're planning to replace it anyway. But you typically want a confident idea what is going to break, and if that break will trigger other problems you didn't have before.

 

[horsepower addiction]

There was not any clear misfires which is why it is constantly a P0300 code and not isolated to one cylinder.

[/QUOTE]
You are misunderstanding the P300 code just because it says P300 random multiple cylinder misfire doesn’t necessarily mean it’s random. it means that the Misfire Monitor has detected more than a 2 percent variance in RPM between the firing of any two (or more) cylinders in the firing order. It could be the same cylinder or cylinders causing it, but it’s not happening consistently so the computer can’t determine which cylinder it is. so it could be isolated to one cylinder or it could also be multiple cylinders. The computer doesn’t have enough data to determine which cylinder or cylinders it is.

wonder why none of the mechanics didn’t do a leak down test.

 

[horsepower addiction]

I wanna know how they determined the spark plugs and the coils were good. Did they just look at them and determine they were goodor did they do an ohm’s test. Because neither one of these are a very good way to test if these parts aregood under a load.

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