I'm trying to diagnose this erratic idle of mine where the car likes to surge when its cold and bog down under load. Its mostly stock (look at my sig). A friend of mine told me he had the same problem on his Monte and pointed out to me what I should replace, but didn't give it a name. Below is what he pointed out to me.

On the throttle body, passenger side, there are two sensors with wires connecting to them. One of them I know is the IAC valve with a 4 wire connector, the other one (mystery, could it be the throttle position sensor?) has three wires going into it (black, green, and yellow) and the following is molded into the side of it: 87653 C1749. Like I said, I think it might be the throttle position sensor, could that be the cause of my weird idle?

How much would another one of them usually go for?

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'91 Firebird
305/TBI/700R4/T-tops
Mods: Catco high flow cat - B&M Shift kit - Taylor 8mm Spiro-Pro's - ACDelco Rapidfire Plugs - K&N Air Filter - Trans Am tail light conversion
Stereo: Pioneer DEH-P8200R - Pioneer 6x9's - Kenwood 8" Tube
'91 Pics

'87 Firebird
2.8L/MPFI/700R4/220K Miles on its original, never been rebuilt engine!
Car being parted and sold, just ask what I have.
'87 Pics

[This message has been edited by pianiy (edited October 13, 2000).]

 

ding ding ding, youre right. Its the tps. and yes that could be your idle problem, only way to know for sure is either hook up a scan tool or digital volt meter, to see what the voltage on it is reading at idle and thru an increase of rpms. You should be under 1.25 at idle, and over 4.0 almost 5.0 at wot, im not sure how to test with dvm because i use a scan tool. tap on the thing when idling and see if idle adjusts, that was my indication that something was wrong with mine. It shouldn't do anything. My harness was simply loose because the clip was broken.
Anyway, that could be it, and of course it could be something else, like a loose or leaking vacum line fuel filter etc.....and on and on. Guys? Maybe you can help him with the meter on that thing since i cant.

And Prices too??? dont know. call chevy dealership.

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ENGINE SPECS:
305 TBI,Open Element,K&N 14x3,Hypertech Stage I,160 Deg. Thermostat,454 GM TBI

STEREO SPECS:
JVC Kalmeleon kdlx3,Infinity Kappa 2way 6x9's,PPI 4x6 Coaxials,PPI PC2400 AMP @ 2ohm
DEI Studio 12" 4ohm DVC,Custom Box:Exactly 1 Cubic Foot

[This message has been edited by snflupigus (edited October 13, 2000).]