Questions from new 17 GT owner.

[z6cyl]

Finally picked up my new to me car today - 2017 GT base manual ruby red, 35K miles, still have 1,000 miles left of factory bumper to bumper warranty. I'm a little disappointed with the cosmetics - it needs some serious paint correction and touchup, much more so than I could tell from pictures. And some Kansas county cop gave me a $140 ticket for 6 over in a 65 (wtf). Otherwise I had a 9 hour drive home to feel things out and I have some questions:

• Is the idle of the 5.0 generally very very slightly lopey - or not perfectly smooth in terms of cylinder firing timing/order? Especially with A/C on - the A/C engages on/off every like 15-30 seconds causing the idle to change/sound a bit off kilter. Is this normal? Seems to do it occasionally with A/C off too.
• I was under the impression this was a stock car but it was loud all the way home and the drone 1k-2k rpms was insane my ears hurt. I looked at mufflers and headers, they seem stock. Haven't gotten under the car but what should I look for? Maybe an x-pipe? what would cause the exhaust to be so loud and drone-y?
• This sounds stupid but I haven't driven a RWD car in a while. When accelerating in any gear hard-ish at 3.5-4K+ rpm, and lifting off suddenly, the car pulls to the left or right for a split second. Is this lift-off traction loss on the rear end? or is this abnormal?
• The shifter in all gears makes this weird noise like.. a rubbing noise. not quite grinding, but like there is a slight contact - it sounds like a cat hissing but very quiet. Its definitely coming from the shifter and not below. normal? weird?
• Lastly - how could i know if the car was ever tuned (or is actively tuned) or had FI kit installed? anyway to tell these things from logs or scanner device?

thanks all

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[MRGTX]

Congrats on picking up a beautiful car!
Unfortunately, it sounds like you have to give this thing a once-over.

First thing I would do is hook up a scan tool and look for any codes. That may answer a lot of questions.

The lopey idle sounds wrong...I wonder if someone reinstalled the stock airbox and got the MAS dirty with grubby fingers?

The exhaust is not right...look for some undercarriage reference pics and get under that car (with proper jackstands). Even if the pieces are all stock, there's probably an incorrectly connected section here or there resulting in a leak? Also check to make sure the stock resonators are in place. The "resonator delete" mod is not uncommon and it could create this kind of experience.

The suspension pulling...definitely not right. Something is loose, probably in the front end. Take it to a good alignment shop ASAP.

The transmission noise...that could be normal...hard to say.

I am getting the sense that someone had some mods on this car and hastily put it back to stock before selling it...if so, the car will very probably be fine, you just have some work to do first. Keep us posted. Really, the car looks like it will be worth the trouble. Good luck!

 

[kluke15]

agreed as above. check for codes. lopey sounds wrong to me (check plugs and maf to start?) but the cycling of the AC is totally normal or at least it is for me. if its droning it most likely has resonator delete in the middle of the car underneath where you are sitting. should be a big suitcase looking muffler. also check the mufflers themselves for being swapped. stock mufflers are pretty fat so you should be able to tell easily. car shouldnt pull like that i would also check alignment and tires/ tire pressure. the shifter noise is probably normal. there is a decent amount of noise from the mt82 so i wouldnt be surprised if its all fine there. you might be able to see if a ford tech can see how many times the car has been flashed or how many start cycles since the last flash and that might give you an idea but i dont think you would really be able to tell if it was tuned or FI and returned to stock unless they left something in place or out of place.

 

[z6cyl]

Congrats on picking up a beautiful car!
Unfortunately, it sounds like you have to give this thing a once-over.

First thing I would do is hook up a scan tool and look for any codes. That may answer a lot of questions.

The lopey idle sounds wrong...I wonder if someone reinstalled the stock airbox and got the MAS dirty with grubby fingers?

The exhaust is not right...look for some undercarriage reference pics and get under that car (with proper jackstands). Even if the pieces are all stock, there's probably an incorrectly connected section here or there resulting in a leak? Also check to make sure the stock resonators are in place. The "resonator delete" mod is not uncommon and it could create this kind of experience.

The suspension pulling...definitely not right. Something is loose, probably in the front end. Take it to a good alignment shop ASAP.

The transmission noise...that could be normal...hard to say.

I am getting the sense that someone had some mods on this car and hastily put it back to stock before selling it...if so, the car will very probably be fine, you just have some work to do first. Keep us posted. Really, the car looks like it will be worth the trouble. Good luck!

thanks for your reply!

I don’t have a scan tool - should one of the auto parts stores tools work for this or should I have my mechanic do this?

My first thought on the exhaust was something with the resonator - I’ll check this today. Hopefully a quick fix in this department.

It has brand new tires and alignment from the dealer, it drives nice and straight. The only time it gets wonky is a full let-off from WOT - I don’t remember this being an issue in prior mustangs I've owned so I’m not sure where to start unless I should get it aligned again..

Will look into the plugs and MAS too for the idle. The idle it’s terrible it just sounds slightly off? I guess you could say

 

[kluke15]

thanks for your reply!

I don’t have a scan tool - should one of the auto parts stores tools work for this or should I have my mechanic do this?

My first thought on the exhaust was something with the resonator - I’ll check this today. Hopefully a quick fix in this department.

It has brand new tires and alignment from the dealer, it drives nice and straight. The only time it gets wonky is a full let-off from WOT - I don’t remember this being an issue in prior mustangs I've owned so I’m not sure where to start unless I should get it aligned again..

Will look into the plugs and MAS too for the idle. The idle it’s terrible it just sounds slightly off? I guess you could say

check plug gaps too. auto store can scan it for free and pull any codes but i would suggest picking up a scan tool. ive got one i spent like 80-100 bucks on and its saved me prob minimum 30 trips and a lot of headaches. ive read some people feel some sway or unsteady at speed not sure if that is what you are feeling. i know it shouldnt NEED parts but the bmr cb005 i think and steeda stop the hop kits prevent the irs from moving so much and that may help you feel more planted in those situations. could also be the stock suspension is just loose or wearing out?

 

[z6cyl]

So no codes, which is good. I sat idled without AC on and it seems fine. The car does shake ever so slightly not sure if that is normal.

Grabbed a bottle of cleaner at parts store so doing MAF/MAS next

 

[z6cyl]

MAF clean completed - idle without AC is fine now. Vacuum seems low at 17? is that normal for these cars? With AC on every-time the compressor or fan click on the idle bounces and steadies and then again when it turns off. Maybe this is normal. Vacuum with AC on is 16 that seems super low too

 

[MRGTX]

MAF clean completed - idle without AC is fine now. Vacuum seems low at 17? is that normal for these cars? With AC on every-time the compressor or fan click on the idle bounces and steadies and then again when it turns off. Maybe this is normal. Vacuum with AC on is 16 that seems super low too

I agree that the vacuum sounds low. IIRC, it should be at least 20 at idle. Someone correct me if I’m wrong...
...but it sounds like you could have leak. How many miles have you put on the car so far? If they had disconnected the battery before selling the car to you, the computer might not be throwing a code yet.

Do you have any cigars handy?

 

[z6cyl]

I agree that the vacuum sounds low. IIRC, it should be at least 20 at idle. Someone correct me if I’m wrong...
...but it sounds like you could have leak. How many miles have you put on the car so far? If they had disconnected the battery before selling the car to you, the computer might not be throwing a code yet.

Do you have any cigars handy?

drove 600 miles yesterday. Should I just go to the dealer for this one (still under warranty)

 

[Flimflamman]

I would go to the dealer and have them look it over. Explain all of your concerns and get those monkey's off your back while you still have bumper-to-bumper. Who cares if they laugh in your face or not. It's your last chance to catch anything that might be covered.

 

[MRGTX]

I would go to the dealer and have them look it over. Explain all of your concerns and get those monkey's off your back while you still have bumper-to-bumper. Who cares if they laugh in your face or not. It's your last chance to catch anything that might be covered.

Agreed on all counts.

 

[Flimflamman]

I agree that the vacuum sounds low. IIRC, it should be at least 20 at idle. Someone correct me if I’m wrong...
...but it sounds like you could have leak. How many miles have you put on the car so far? If they had disconnected the battery before selling the car to you, the computer might not be throwing a code yet.

Do you have any cigars handy?

That dude is a trip. lol

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