I've got a 91 t2 with 79.000 miles on it. The car starts up, idles fine, seems normal untill you pull off. I can drive around the block and hammer it, car boosts up and hauls ***, until about the third time and at about 4k it falls on it's face and cel pops on. The car goes into limp mode and runs like ****.

I can turn it off, start it back and cel goes out, car goes back to boost. I've tried 3 different ecu's, 2 boost sensors. What the hell could it be? Is there any other sensor I'm missing?

 

BRYAN hope all is well

What check engine code are you getting?. I had an issue with a 90 gxl that sounds similar.
See if its the OMP I have one if you want it.
give me an adress.and if all s5 are the same

jOHNY

 

yep ..sounds like Limp Mode..omp problem as Johnny Said..I am sort of Glad That I have an S4..as most of the Guys that Have S5's seem to Run into an OMP problem often..

 

Thanks Johny! Here's the strange thing..it doesn't give a code. You ground the jumper and turn the key on, the light comes on, goes out, then comes on and stays on. Im baffled.