Low RPM, no throttle response

[ExiledWeegie]

hi guys,

weird one, car is driving perfectly, but on occasion when I start her up she sits at 500rpm with no throttle response at all, then slowly it will come back to life, the revs will slowly rise to 750rpm and the throttle will come back, sometimes take 10 seconds, sometimes takes 30 seconds.

its done it a couple of times now, always when warm and always when the car is facing uphill.

any ideas? fuel draining back to the tank? throttle sensor? no codes for anything and otherwise drives great.

 

[nd-photo.nl]

Throttle body maybe? Do a TBA alignment and check if that works out ok (it will cycle to minimum / maximum positions)

VCDS Throttle Body Alignment TBA

If you have Ross-Tech VCDS, aligning the throttle body after cleaning it or replacing it is simple. Here are the steps: Connect VCDS to the car's OBDII port. Turn the key on but do not start the car. [Select] [01 - Engine] [Basic Settings - 04] Group 060 [Go!] It should say "Basic Settings: OFF"...

www.vwvortex.com

 

[ExiledWeegie]

I dont think its that, its had a few alignments in the last few months (the TB itself is only 4 months old) and this is a really random problem, it only happens under the specific set of conditions I mentioned in the first post, its a wierd one, I'll give it another alignment tomorrow just to rule it out though.

 

[ExiledWeegie]

this problem is back big time, with it being very warm here right now its happening much more regular, narrowed it down to temp related, angle of the car does nothing. when it happens if i unplug the IAT it kicks back into life, revs fine and throttle works again, until next time its very warm, put a new IAT in it and tested both throttle bodies thats i have and does the same thing. any ideas?

 

[Connor H]

Have you tried replacing that specific sensor ?

Any error codes? Cant lie ive not heard this one before

 

[ExiledWeegie]

yeah tried replacing the sensor and hasnt made any difference, no error codes either.

theres a couple of pages online about this exact problem but it all pointed to the Unitronic map that the cars had on them,
i got hold of the guy who mapped mine last night and he says no it wasnt unitronic on mine and basically that was it, no offers
to check the map or anything so i got hold of another local mapper who says it could be a bad map causing it so hes willing
to put a standard map back on it and see if problem is gone, then remap it again and tweak as needed.