Strange Acceleration Hesitation

[Leigh_bullitt]

Hi All
First and Foremost Happy new year.

So I have a 2020 Bullitt and some strange hesitation has started to happen and I’ve found other people with the same problem but no solution yet.

The Problem
So imagine I’m cruising in 5th at say 50-60mph and I take my foot off the gas. As I reapply their is this sudden jerk or hesitation that happens. Almost like power goes flat for less than a second. If I’m in lower gears it’s not noticeable. Only when cruising.

it seems a bit intermittent too. I notice the car doesn’t run quite as well at lower rpm’s when this happens it can feel a little jerky when driving in traffic etc.

But then it will go as smooth as silk and run great again.
Any ideas ?.

changed spark plugs
Car has 30,000 miles from new

it has a tune but I this is confirmed to happen when returned to stock as well.
Always use shell or BP 98 fuel ( 93 US ).

any help would be appreciated.
Cheers

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[Leigh_bullitt]

Could the MAF has something to do with it?.
can the MAF be working ok but still be slightly contaminated?.
might explain it being intermittent ?.
Thanks

 

[MiamiGT350]

I would clean the throttle body and maf. Anything severely wrong with the throttle body would throw codes and/or a dash wrench w/ limp mode.

Perhaps TC is intervening. Does the issue go away with traction control disabled? Be careful testing!

Also try disconnecting the battery for a few mins. Then go on a drive where you smoothly accelerate to highway speeds a few times. Then a few times being more aggressive.

Good luck!

 

[Leigh_bullitt]

Thanks for replying.
Yeh I’m going to try that first.
I may also pick up a new maf sensor on the cheap to see if that changes anything too.

 

[NGOT8R]

Sounds like you’re lugging the engine. When you’re cruising in 5th gear, and lift off the accelerator, the speed and rpm decreases. Getting back on the accelerator then causes the engine to lug. Try staying in 3rd gear and then 4th gear at 50-60 mph, lift off the accelerator and press on the accelerator pedal again. It shouldn’t lug (especially in 3rd gear) if the rpm’s are higher.

I never go into 5th gear even on the highway until I hit 70+ mph and I almost never use 6th gear at all.

 

[KingKona]

Thanks for replying.
Yeh I’m going to try that first.
I may also pick up a new maf sensor on the cheap to see if that changes anything too.

No.

Do NOT do this. Do NOT fuck with your car's electronics un-necessarily.

Do not replace your OEM MAFS with a cheap piece of shit after-market one.

There is almost no reason your MAFS would be a problem. It's either your driving against the 1080R's logic, or you've damaged something modifying something.

If you must do something, just get some MAFS cleaner and hose it down.

 

[robvas]

Can you datalog the car? Would recording a video show anything or capture any noises?

I would think if it was MAF related you'd notice other issues.

 

[Leigh_bullitt]

Thanks
Yeh I’ll do a datalog and see if it picks it up.
some other people with the same problem say it’s just the way ford has it set up because of emissions etc ?.

 

[MiamiGT350]

Thanks for replying.
Yeh I’m going to try that first.
I may also pick up a new maf sensor on the cheap to see if that changes anything too.

No, i don't recommend a new one, let alone a "cheap one." I agree with @KingKona. Anything severely wrong meriting a replacement will throw codes and or wrench lights.

Cleaning the MAF and throttle body might help overall, but I suspect it is driving habits and/or the TC intervening. These cars can spin tires at highway speeds...

 

[Leigh_bullitt]

I’ll take it for a spin with the TC switched off and report back.
Thanks

 

[KingKona]

I’ll take it for a spin with the TC switched off and report back.
Thanks

You can't be cruising along in top gear, jump off the throttle, then jump back on, and not expect the drivetrain to hesitate.

Your obsessing and repeating that ON/OFF throttle behavior just to re-enforce to yourself that something is wrong, doesn't mean something is actually wrong.

 

[Leigh_bullitt]

Noooo not at all.
Nobody keeps their foot on the gas all the time.
imagine your driving 60 in 5th and your engine braking to go round a slight corner.
What do you do ?.
you take you foot off the gas but when it’s reapplied you get the sudden jerk.

 

[NGOT8R]

The good news here is, I don’t think there’s any thing wrong with your car. This is actually something that anyone with a manual transmission car can replicate if the speed/rpm is too low when getting off and back on the throttle. Any noise (such as an clunk) associated with it is going to be drivetrain backlash.

 

[KingKona]

Noooo not at all.
Nobody keeps their foot on the gas all the time.
imagine your driving 60 in 5th and your engine braking to go round a slight corner.
What do you do ?.
you take you foot off the gas but when it’s reapplied you get the sudden jerk.

You're jumping off and then back onto the throttle at low RPMs in 5th or 6th gear. Yes, it's your fault.

These aren't large-displacement, low RPM torque-monster engines, these are high RPM screamer engines. They will lug at low RPMs.

 

[NGOT8R]

Next time you’re out driving and the engine lugs, just downshift a gear and then get back on the throttle. If it still lugs, downshift another gear and all should be good. I can’t see you needing to drop down more than 1-2 gears to straighten things out.

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