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car runs absolutely terrible, update #1


3pt1lumina

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Okay, my Lumina has been off the road since October. I start it once a week and drive it around in the little storage complex it's at. I let it idle and the car has been running fine.

 

Now, tonight I go over, start it and it sounds as if it is misfiring. The car has lost no performance and still accelerates great. Since there was no salt I took it out on the road (after the engine warmed up) and just put it to the floor a few times. No difference at all. Idling the car runs terrible though. It had to have run 30 minutes, and there was no difference.

 

So what the hell is going on? The IAC is about a year old, so is the EGR. The battery did die once on me about a month ago, but I didn't lose any of my radio presets so I'm assuming that the ECM didn't lose it's memory.

 

I'm going to try an idle relearn, if that doesn't work what the hell do I do next?

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clean the iac port, egr port......

check for nesting albotrosses in the airbox? (I found a nest in my 95 CS!)

 

done plugs recently?

Any chance of degrading gas? maybe add a thing of fuel stabilizer?

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Try running some fuel system cleaner through it...

 

Put some DRYGAS or something similar in your fuel tank. You might just have some water in your fuel lines. That would have the most negative effect at ignition.

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The car has ACDelco Plugs/Wires which are about 1.5 years old. They have maybe 5k on them.

 

I put some Sta-Bil in there right before I put it away. I suppose I can try some drygas..never did think of that.

 

What baffles me is the car still performs excellent. When I slam on the gas, it gets right up just as it always has. No hesitation, bucking, nothing..nice and smooth.

 

Drygas and idle relearn are next on the list... will update probably tomorrow after work. Thanks guys. Anymore ideas send 'em along.

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Check/listen for arcing.. Simply could be one of the boots for the spark plug wires came loose, cracked/dried out, etc from the cold/start up and it is causing a miss.. Would be my guess since it just started..

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Did an idle relearn. The car ran good for about 30 seconds afterwords, then slowly it turned to crap again. I revved the engine a little bit and it just doesn't idle right, period.

 

Okay so my next step is drygas, then I'm going to look at my plugs/wires for arcing or crappy looking wires. I just don't get it, last Friday I started it and it ran awesome, a week later and it's pure crap. But no power loss driving it... I'm baffled.

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if you can.... see if the cruise control works. It is fed off the vac. circuit that usaully suffers a failure in these cars. The climate control is as well, but may not be as "reactive" to a leak. (ie change where air is coming out, from vent to floor to defrost ...)

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his vents would be at the floor if the cruise didnt work. But a different vac leak can occur and not even affect the HVAC or Cruise

true. but I have never had a leak elsewhere, except... for when the lines beneath the plenum are old and cracked.... So inspect there next.

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Okay I went over there for over an hour. Put some drygas in... no difference. I checked the plug wires to make sure nothing came loose. From what I can see, there is also no arcing. All vacuum lines seem to be okay as they are all tight and look new. I obviously can't see under the plenum so I can't say much for that.

 

I made an observation. When I put my foot on and off the brake, the RPM's fluctuated ~200 or so. I know this is related to vacuum but I don't know anything else about this.

 

Now, I have a new IAC (extra) so I tried putting that in. First attempt the car started, idled funny due to relearning the new IAC, then slowly started to increase RPM's. I decided to shut the car down when the damn thing reached almost 4k. I took it back out, adjusted the pintle, then put it back in. This time the car kept stalling in gear. Frustrated, I put the old one back in, which again, was new 7/04. The car RPM wise, idled like it's normal self IN DRIVE ONLY but still sounding like it's misfiring. In park/neutral, it sounds like a goddamn lawnmower and idled ~1500rpms. Typically my car idles at 1k in park, and 800 in drive and it doesn't go "sputter sputter"...

 

There are no mice nests, the garage is dry with a concrete floor. The exhaust doesn't smell all that funny, seems to be running at it's normal operating temperature, no SES, (car has had a long history with a code 32, but no one can figure it out including the dealer, only comes on over 55mph.) yet it won't idle. I am really really really frustrated right now.

 

Here's some random ideas I have:

-TPS

-O2 sensors

-Coilpacks (is there a way to check them?)

-Fouled plugs/bad wire

-ICM

 

Help, I'm giving up for the night. Maybe someone will come up with a solution here.

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I duno if you mentioned this before, if so Im sorry, but maybe it could be with the EGR valve. Take it off and start it up, if the RPMs go up to about 4k, everything *should* be good, if it still idles around 1500ish RPMs its clogged with carbon. (I duno when the last time you cleaned it was)

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pop the egr off and clean the port, basically....

 

I think to relearn a new IAC, you have to turn the key to the on position (don't start) and wait maybe 15 seconds.

 

p.s

I read in the 94 3100 service manual that it is relearned with a basic idle relearn lol...(duh!)

 

resetting pintle (iac valve) position. basically to reset it on the 3100 turn key on for 5 seconds, then off for 10. same idea as 3.1

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i'd pop off the EGR and clean it and its port out with brake or carb cleaner, if it just sounds like its missing, are you sure you don't have an exhaust leak? i have seen the 02 sensor break off and while the car would stlll run "acceptable" it would sound like hell.

 

but mabie buy a brand new IAC again, and do what crazy k said about learning the IACs position, and when i changed mine it took a hour or so of driving for it to fully learn what was up.

 

then i'd check for a cracked spark plug, something stupid that you would kick yourself for later.

 

then my next step would be to start replacing coil packs.

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i'd pop off the EGR and clean it and its port out with brake or carb cleaner, if it just sounds like its missing, are you sure you don't have an exhaust leak? i have seen the 02 sensor break off and while the car would stlll run "acceptable" it would sound like hell.

 

but mabie buy a brand new IAC again, and do what crazy k said about learning the IACs position, and when i changed mine it took a hour or so of driving for it to fully learn what was up.

 

then i'd check for a cracked spark plug, something stupid that you would kick yourself for later.

 

then my next step would be to start replacing coil packs.

x2 ....

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i've had to replace rusted coil packs before. It was a really expensive dealer job b/c I couldn't get them off...they were rusted on. gl hf if that's what you've gotta deal with.

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