i have the idle screw backed all the way out and the car idles over 1000rpm i cant get it any lower and when it is at idle about every 5-10 seconds the motor will surge and the tach will drop to about 400rpm for a quick second kind of like when you turn your a\c on but only worse and this repeats until it finaly drops so low it die please help. i have replace plugs,wires,cap,rotor,and egr valve could this be my tps sensor or 02 sensor

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92 b4c 305 t-5
ported plenum
58mm TB
dynomax headers
msd coil
adjustable fuel regulator
air foil
K&N
TB coolant bypass
smog pump bypass
worldclass t-5
custom built y pipe
hi-flow cats
flowmaster
hurst shifter
3.73 rear

 

Check you TPS, 02, and MAF sensors. Also check your fuel pressure regulator. Is there any black soot on the tip of your tailpipes? If there is you may be running rich (too much fuel). I had a similar problem on 2 different cars....one had a bad fuel pressure regulator, the other had a bad fuel pump.

Also check your spark plugs for soot too.

I hope this works for you.

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92 Camaro RS LO3, 5-spd, T-tops
Mechanics:
Open Air Element w/K&N Filter, Flowmaster 3" Cat-back Exhaust, Z28 Grille w/aftmkt fog lamps
Electronics:
Alpine 8030 Alarm System, Valentine One Radar Detector (How did I ever drive without one?), Pioneer DEH 7450 Head Unit w/6-pack CD changer, Pioneer DEQ 7600 Sound Processor, 2 Kenwood KAC-90 Amps powering 2 12" Pro Red subs and 4 Infiniti speakers.
NEXT UP: SLP 1 3/4" Headers/Y-pipe, Centerforce Dual Friction Clutch kit

 

Doesn't sound like the O2 sensor. Does it do it all the time, or only when the car's warmed up? If it does it all the time then you can definitely rule out the O2, because it only controls the air-fuel ratio when the car is in closed loop (when the car is warmed up). You might want to check the IAC. And playing with the idle screw will cause more problems and make it harder to diagnose, although I do realize it may help keep the car running at this point. Also make sure there isn't any carbon built up behind the trottle plates or in the IAC passage. And you have a MAP, not a MAF.

[This message has been edited by ViciousZ (edited November 18, 2000).]

 

the car has definetly been runing rich since i removed the smog pump and a.i.r system about 4 months ago but and this problem just started 2 weeks ago and yes it only does this after the engine has warmed up for a couple of minutes. the car also seems to run alot stronger until it warms up. and yes it is a map system.

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92 b4c 305 t-5
ported plenum
58mm TB
dynomax headers
msd coil
adjustable fuel regulator
air foil
K&N
TB coolant bypass
smog pump bypass
worldclass t-5
custom built y pipe
hi-flow cats
flowmaster
hurst shifter
3.73 rear

 

B4C,

I'd second the vote for taking a close look at the IAC stepper motor and air passages. You might also want to inspect the throttle valve shaft for wear, allowing the throttle plates to get stuck in the bores at a given position. I'm not sure how old you 58mm TB is, but if the plate alignment isn't correct, you can have the throttle stick open a bit without realizing it.

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Later,
Vader
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"Make Me Bad"
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