Poor throttle response on tip in

[devin2589]

2019 Bullitt, long tubes and x pipe are the only mods. I’ve attached a video for reference. On throttle tip in, the car bogs and tries to stall. After initial tip in, it responds perfectly fine. If I hot start the car and try to drive immediately. It’ll buck and sputter for a few seconds during cat warm up.

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[NGOT8R]

How does the throttle body look (clean or dirty)? Try cleaning it and focusing on the throttle blade shaft where each side enters the housing. In addition, give the MAF sensor a good cleaning using mass air flow sensor cleaner.

 

[Leigh_bullitt]

2019 Bullitt, long tubes and x pipe are the only mods. I’ve attached a video for reference. On throttle tip in, the car bogs and tries to stall. After initial tip in, it responds perfectly fine. If I hot start the car and try to drive immediately. It’ll buck and sputter for a few seconds during cat warm up.

Do you have a tune ?.
do you have an obd reader ?.
Any codes ?.

could be anything at this point without seeing a datalog.
but yes check the main things first.
Maf
Air filter
Throttle body

disconnect the IMRC and see if it improves.
two electrical connectors at the back of the motor on the top.
disconect with engine off and then start and see if it helps.

 

[Leigh_bullitt]

2019 Bullitt, long tubes and x pipe are the only mods. I’ve attached a video for reference. On throttle tip in, the car bogs and tries to stall. After initial tip in, it responds perfectly fine. If I hot start the car and try to drive immediately. It’ll buck and sputter for a few seconds during cat warm up.

My 2020 Bullitt will sometimes do this after filling up.
First start will big down suddenly.

 

[devin2589]

How does the throttle body look (clean or dirty)? Try cleaning it and focusing on the throttle blade shaft where each side enters the housing. In addition, give the MAF sensor a good cleaning using mass air flow sensor cleaner.

the throttle body blade does have something that looks like it melted onto the face of it. Won’t come off without actually sanding it down. It’s on the face of the blade so not sure if it would effect anything.

 

[devin2589]

Do you have a tune ?.
do you have an obd reader ?.
Any codes ?.

could be anything at this point without seeing a datalog.
but yes check the main things first.
Maf
Air filter
Throttle body

disconnect the IMRC and see if it improves.
two electrical connectors at the back of the motor on the top.
disconect with engine off and then start and see if it helps.

No tune
No codes

air filter is new, maf is clean, throttle body I mentioned in the above post. Maybe that’s contributing to it? Vac lines on the imrc’s look fine. Vac lines on the front of the manifold could be better. Not acting like a vac leak but I’ll change those for safe measure. I’ll disconnect the imrc’s and report back.

 

[NGOT8R]

the throttle body blade does have something that looks like it melted onto the face of it. Won’t come off without actually sanding it down. It’s on the face of the blade so not sure if it would effect anything.

Try using some brake and parts cleaner on a rag and see if that removes it. Is the shaft gunked up where it entered the tb housing?

 

[devin2589]

My 2020 Bullitt will sometimes do this after filling up.
First start will big down suddenly.

happens every hot start for me. It just kind of popped up out of no where. Maybe purge valve or evap causing the issue. I can fill my tank without it stopping me so I assumed it was venting properly.

 

[NGOT8R]

MAF could still be dirty (unless of course you’ve cleaned it recently). Either pull the sensor from the housing and spray it down or remove the whole housing with the sensor in it and spray it down really good.

 

[NGOT8R]

Clean tb as in like this. I’ve had to do it a few times before I installed a JPC breather kit because oil must would get sucked back into the tb and intake.

 

[Leigh_bullitt]

the throttle body blade does have something that looks like it melted onto the face of it. Won’t come off without actually sanding it down. It’s on the face of the blade so not sure if it would effect anything.

Not really the face of the blade won’t affect it.
With the blade it’s the opening and closing that would cause it to happen. If it moves freely that won’t be your problem.

try unplugging the IMRC runners

 

[NightmareMoon]

Don’t you need a tune with headers? Headers should change the VE of the engine.

What are your AF numbers doing when it bogs?

 

[NGOT8R]

Look closely at the areas where the red arrows are pointing in this pic (on both sides of the blade). If they’re dirty and gunked up, it can cause trouble.

 

[Leigh_bullitt]

Look closely at the areas where the red arrows are pointing in this pic (on both sides of the blade). If they’re dirty and gunked up, it can cause trouble.

Yep that’s where you need to check.
If the butterfly valve is binding it will upset the ecu.
Try the IMRC they will cause bogging down if stuck closed

 

[devin2589]

I’m sure the headers messed with the transport delay for the o2 sensors. This issue occurred suddenly out of no where. I’ll check a/f when testing next time. TB is clean (aside from gunk on the face that would require sanding to remove.) MAF visually looks fine. I’ll grab some cleaner just to cross that off as the potential issue. If that doesn’t resolve it then I’ll disconnect the runners. Thanks for the responses guys.

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