94 st idle/running issues Options

[Kennyb8709]

Car: 1994 st manual trans all stock apart from eBay intake on car prior to purchase 140k on the clock.

Background: car was purchased a month or two ago, immediate tune up was done (plugs wires cap and rotor valve cover gasket and pass window switch fixed) also installed HID's and a radio to demo to customers at my work. Car ran tip top for about 2 weeks.

Problem and symptoms: when starting and idle car idles at approximately 500 or lower RPMS. Car stall occasionally when idling after start up. For first few mins of low idle engine will not rev above 1k if I'm lucky. When car decides to cooperate (anywhere from one minute to five) she revs till red line however 1k to 2.5k severely bogs and its slow after 2.5k. Car has almost no power under load. Passing on the highway is next to impossible.

I need some help here people. Any ideas?

[Kennyb8709]

Update: replaced the TPS because the plastic housing was cracked, no improvement. Going to check out the EGR tomorrow because it seems to be sticking until the car warms up.

[Box]

Idle Air Control Valve.

[timdog1720]

/\ /\ /\ /\ /\ I agree

[IfWeChoose]

A faulty IAC only affects the car immediately after start up and until the car warms up. When accelerating the IAC has no additional function. Don't know what else it might be but I would dismiss a faulty IAC. Also, IAC will have absolutely no influence on power under load.

How's your throttle body? MAF? CAT? We'll go on after checking all these out.

[Box]

If the IACV is stuck open it'll cause problems after hitting operating temperature. The car doesn't have a MAF, has a MAP though. Those are easy enough to check. Now that I think about it, I'd put my money on the MAP sensor.

[IfWeChoose]

Sorry I was a little drunk when I posted that lol!

But if the IAC was stuck open, he wouldn't have idling/stalling issues after a cold start up. He'll have excessively high idles after being warm though and no real loss of power.

I wonder what he has found out about his EGR

EDIT: avoided double post

This post has been edited by IfWeChoose: Jun 8, 2013 - 10:33 AM

[Box]

Like I said I'm willing to bet it's the MAP sensor, as those will cause all kinds of problems if they're not working correctly. When it's acting up, pull the vacuum line off the MAP and see if anything changes. If it doesn't then there's your problem.

[Kennyb8709]

Thanks so much for the replies thusfar everybody,i made a ****ty video of my issues today while i was at work. here is the youtube link! please ignore my amazing camera skills and HD video /s.

http://www.youtube.com/watch?v=0rzL-KxtjQg

[Kennyb8709]

Bump and replacing the IAC tomorrow. Hope that solves it.

[travisxcore]

Open up your dizzy, and check your pickup. It might have gone bad. I know when mine did my symptoms were:
-Starting issues
-Rough idle
-Misfire
-Occasional dead cylinder
-Bogging down after 3k
-Bogging down under load

Although I had a check engine light for it but I never bothered to check it cause it had been stuck on for a year.

[Kennyb8709]

Ill check it since its easy to get too but I did replace the cap and rotor with my purchase tune up. Like I said though wont hurt to check.

[travisxcore]

Your pickup is behind the cap and rotor. It looks like rectangular copper plate with a coil pack around it.

[IfWeChoose]

Did you ever check your MAP? Do what Box said earlier in the thread to test it.

[Kennyb8709]

checked MAP, MAp was good, replaced IAC and had a small improvement, ended up adjusting distributor (loosening and rotating) and got her back to normal apart from a slightly high idle. im just glad my baby is drivable again!

thank you for all the help guys

[IfWeChoose]

Sweet man! Distributor was the next thing I was gonna suggest. Good job man!