Issues with throttle sticking

[ice445]

So I've been seeing this more and more lately, issues with the throttle arbitrarily sticking at certain RPM's after I clutch in to shift. What I mean by this, is as I clutch in, the revs start to fall but then stop, and the throttle just holds open at a consistent RPM, and will stay there either for a brief period of time (3-7 seconds), or in two cases at higher elevation, indefinitely. I seriously had two instances back to back where it stayed open for almost 20 seconds, I had to clutch in and downshift to activate the rev match to fix it. Seems to happen more often in the higher gears, especially after I go WOT. I know the car will rev hang for emissions, but this doesn't seem right. Especially since if I try to shift anyway the car bucks horribly because the RPM is way too high. How is this not throwing any codes? The throttle itself always seems to respond when I do something with the gas, but clutching in to shift seems to cause these issues. It's been getting cooler and doing it more often, so maybe an issue with unmetered air? I'm going to check all my intake connections, but so far I'm stumped.

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[Elp_jc]

Any mods? You should start there. And also be VERY specific when the revs hang. With the clutch in and in gear? In N and clutch in? In N and clutch out? I'm suspecting a rev-match logic issue, rather than the throttle-body... but that depends if you were in N (no rev-match input), or in gear. And also if in all gears, or just one. You need to find a pattern, and be able to duplicate it at will, or you'd be wasting your time at a dealer. Let us know.

 

[ice445]

Any mods? You should start there. And also be VERY specific when the revs hang. With the clutch in and in gear? In N and clutch in? In N and clutch out? I'm suspecting a rev-match logic issue, rather than the throttle-body... but that depends if you were in N (no rev-match input), or in gear. And also if in all gears, or just one. You need to find a pattern, and be able to duplicate it at will, or you'd be wasting your time at a dealer. Let us know.

Clutch in, in neutral. Seems most common trying to shift from 3rd to 4th, when I go to grab 4th but before I enter the gate. I think its an unmetered air problem because I watched my AFR at WOT and it only got to like 12.9. Should be 11's on stock tune. I have no mods but a muffler delete

 

[Elp_jc]

Probably. At least you can eliminate rev-matching since tranny was in N. Did you check for any soft codes with FORScan?

 

[ice445]

Probably. At least you can eliminate rev-matching since tranny was in N. Did you check for any soft codes with FORScan?

I need to data log the car and see if I can find anything out of place. I'll also turn off rev match to double check it isn't that.

 

[ZM5.0]

Did you ever find the issue.. I’ve had similar experiences with my 20.. after some wot pulls rpms will hold high and not decel like normal. Lund e85 tune. They told me it’s just a characteristic

 

[ice445]

Did you ever find the issue.. I’ve had similar experiences with my 20.. after some wot pulls rpms will hold high and not decel like normal. Lund e85 tune. They told me it’s just a characteristic

I never found an actual solution, but it got better over time. Still does it occasionally, but I've found a way to drive around it for the most part. The most common situation it seems to happen is if you're WOT, shift, back to full throttle, and then let off because you're going too fast. If you double clutch into the next gear it fixes it (clutch - neutral - clutch - next gear)

I also have never see it happen if the traction control is off. Maybe the timing pull it does to control wheel slip messes with things and creates that problem. Not entirely sure. But I haven't spent enough time with TC off to properly test it.

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