i have an 88 multi port fuel injected v6 camaro and it has an unstable idle. I have redone the timing and i have a code reader and the code reader tells me that my throttle position sensor has a low signal voltage. I think that a wire is stripped somewhere and it is grounding off into the block. I have took my alternator off and followed the wires from the throttle body all the way to the ECM. I have found nothing. Its funny though, because i have to hold the brake down with my left foot and feather the gas with my right. After a while of driving when the engine is hot, when i take off from a stop, it is a VERY weak acceleration. Can someone please help me?

Do you have a digital voltmeter? There are 3 wires on sensor.Black is ground,gray is 5 volt reference and dark blue is signal wire.
Put voltmeter red lead on dark blue wire and black meter lead on a good ground.You should have .5 volts at idle and 5 volts wide open throttle.Be sure you have key turned on engine off when doing these checks.Write back your findings please.It's starting to irritate me when I and others give out info and NEVER hear back from the guy asking the question!!

thank you for your help. I have a voltage tester and i connected it from the gray wire to the black wire and it said i get .25 volts. from blue to black i get no reading. from blue to gray i get .25 volts again. do you know what this could mean? is my battery not putting out enough juice from it?

I just went out there and turned the engine on and put the volt meter to it and idle was 4.81 volts and wide open throttle was 4.81 volts. i am still losing power somewhere

Nate have you changed the sensor yet. It sounds like it's bad. also when they go bad the EGR valve usually goes to. After you cange the TPS if you don't have much vacumn and your brakes feel spongy the EGR is bad also. Goodluck

nate
Go back and recheck the readings that sschevyfan asked about. All readings are with key on & motor not running. From the grey wire to ground you should have about 5 volts (4.81 is close enuff). Then check the blue wire to ground. With the throttle body in idle position, you should read about .5 VDC. With the throttle body at wide open throttle, you should read close to 5 VDC. Sounds as if you need to adjust the TPS to .5VDC in idle position.

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Rick Schaefer
68 Camaro
72 El Camino (http://members.home.net/jimmy4/rick1972elky.html)
TPI350/700r4 (http://chevelles.com/showroom/ricks%20motor%20-L)

how is EGR related to the vacuum? The EGR takes exhaust and lowers the amount of nitrus oxides in it and then feeds it to the caurberator or the throttle body. Anyways the TPS is not bad, i have alreadt replaced it, but it has slide joints where the scres go in to it. If i loosen them and turn the angle of he TPS, will it help?

I'm not sure what the above statement was about the egr?? The tps and egr are not related in any way. There must be some confusion.Those slots you referred to are so you can adjust the voltage reading at closed throttle(idle position).Are you using a DIGITAL voltmeter? Never use an analog ( the ones with the needle) when working on computer circuits.Turn key on (engine off) and hook a digital meter up to blue wire and slide tps sensor so you get .5 volts with the throttle closed.Simple. Just make sure you have the 5 volt reference voltage on the gray wire I asked you to check or all this is just wasted time.One post your saying it's .25 volts and the next your saying 4.81.It has to be a for sure 4.8 or higher ALL THE TIME and not changing it's value.If it's changing then you have other problems to address.Again please keep us informed.

Where are you nate??!! What is going on with your car?

i have checked it. I am using an analog voltmeter (the ones with the needles) and it says 4.8 with key turned on and engine off. Another problem i would like to address is that the code reader says that the oxygen sensor and the mass air sensor's signal voltages are low too. My car runs really bad after a little ways of driving. I think that it is related to the mass air sensor. The throttle sensor is a hard one to figure out because i have traced the wires all the way from the sensor to the PROM and everything is fine. I don't know what to do