Mechanics

WONT START, ODD BEHAVIOR...

1999 Audi A4

1999 Audi A4 4 cyl All Wheel Drive Manual 130XXX miles

the car was running fine, had died on the owner once but restarted, then the other day it just died and wouldnt restart. There was a code for throttle position sensor malfunction / inop. The check engine light isnt steady on, sometimes blinking erratically, sometimes solid on but not for long, and sometimes barely coming on and flashing erratically. The fuel pump relay also sometimes clicks on and off erratically. I was trying to find out where the power flow is to supply the ecu with power and where the ground for the ecu is to see if maybe something has a bad connection on it somewhere. The ecu was modified, has a setting for completely stock, and modified (for performance) but that dosent work either, I assume because of the possible power problem or whatever may be going on with the ecu / car. Hopefully someone else has experienced this on a '99 (or similar) A4 with the 1.8T

some questions:

what's the resistance range and terminals for the TPS? (So I can determine if its bad or not). There is 5v going to the throttle valve housing for the TPS and closed throttle position switch.

with the key on engine off, is the check engine light supposed to be on on this make and model?

does the ECU/PCM directly control the CEL?

any ideas why the CEL and fuel pump relay would be going on and off erratically?

also, while sitting with key on engine off, I heard a clicking sound in the throttle valve assembly and noticed the metal part where the throttle cable is was moving kind of as if someone were pressing the gas (but fast and erratic. And just the metal part directly connected to the throttle valve)
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Tmcxba
April 9, 2010.



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