tdrimer

So, I have this annoying hesitation that has been going on a while. Plugs, cap, wires, vac lines all changed in past 500 miles. FPR has been checked and fuel pressure is solid.

Car hesitates when really leaning into it...bucking, hesitation, etc.

Today i took the car out to warm it up a bit. but i drove it differently than normal to see where these hesitations start and end.

1st gear - No hesitating (no boost)
2nd gear - hesitation/bucking (with boost)
3rd gear - same as second
4th gear - sames as third
5th gear - sames as above

Heres the difference today though that I saw. when driving without leaning into it...just cruising - NO BOOST - the car runs smooth as silk. When getting into boost...even just the littlest bit, the hesitating and bucking begins. let off gas - goes back to normal, all gears except first with no boost.

Additionally - (and yes, i know this is bad but was testing) when i am leaning into throttle, if I push on the clutch and keep on the gas, while in boost - the rpms obviously don't move AND the hesitation stops. Let out clutch - still in boost - hesitation begins. push in clutch - while on the gas IN BOOST - goes away, let out clutch still in boost - comes right back.

PS - doesn't matter how much into boost...a little or a lot...this is happening. as soon as boost begins...

MAF was checked about 1000 miles ago when all this started, but was told it was good. Does this seem like Turbo, Vac or Maf issue??

Any help appreciated. I feel like i am at least starting to understand the symptoms and when they happen.

konakat

Sounds like a worn AFM track to me. Could also possibly be a clogged cat. Vacuum is always a possibility for pretty much every problem, so it would probably be prudent to check that first, then check the others.

Jfrahm

This is often a big air leak. Cracked or loose hose, cracked J boot, etc. As suggested it could be an AFM or MAF issue also. If you have not found the issue it'd be helpful to provide a lot more detail about your car and mods.

mytrplseven

TPS switch has two contacts in it. One opens just as the throttle body opens and the other closes when your TB goes to nearly wide open throttle position. If that internal set of contacts are faulty, it won't let the engine go to full rich for agressive acceleration. You can check this at the DME connector with an ohm meter and seeing if the input from the TPS is coming through when WOT is selected. Terminal 3 on the DME connector should go from open or infinity to 0 ohms when WOT is selected. The other test lead should be at ground while doing this check. Terminal 2 is for testing the closed throttle position. The reading at closed throttle should be 0 ohms until you just crack the throttle open and then it will read infinity or very high resistance. If the readings aren't as such, the throttle body will have to be removed to test the switch itself.