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high idle with a random misfire

BoostedPontiac

BoostedPontiac

Regal GS Level Member
I would like to see what could be causing her to idle high. It idles around 1200 to 1400? She will also randomly misfire every once in a while. What could cause this?
 


I'm sure someone more experienced can and will chime in, but mass air flow, throttle position sensor, vacuum leak. Could probably use a tune up if you haven't already done plugs and wires

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I had the same problem. Try this. Turn the key on and press the gas pedal to the floor hold it for 3 sec, let off, pump it to the floor 5 times in 7 sec let off Turn key off then start it . See if this fixes the high idle. If not follow Toms suggestions.
 
More info is really needed. You wouldnt go to a shop and say what you said, because they'd just look at you with a dumb look because they have no idea what you are talking about and what you drive.


What do you drive?

Any recent repairs/maintence done?

Modded or stock?

What else do we need to know about the vehicle to help?

What have you tried?
 
I drive a 1999 Grand Prix with a cammed L67. I bought plugs, wires, oil, and an oil filter but need a day off to install. The car is mildly modded. I havent tried anything tofix the issue because it happened on my way to work today.
 


lewis1952 said:
I had the same problem. Try this. Turn the key on and press the gas pedal to the floor hold it for 3 sec, let off, pump it to the floor 5 times in 7 sec let off Turn key off then start it . See if this fixes the high idle. If not follow Toms suggestions.
Click to expand...

Is that some kind of idle re-learn?
 
With a NIC cam, the code P0300 needs to be shut off.

But I think you need to start with swapping those parts and looking for a vacuum leak. I'd hope you have some sort of scan gauge or whatever to help montior what the car is doing.
 


I also found out I need a new tps. Would low fluid in the trans make is shift horrible. I thought my pcs was going out but I found my trans dipstick was very loose.
 


With that cam, was any programming down to the pcm?

I've seen idle be vacuum leak, throttle/cruise cables bound/out of place on strut tower, TPS, tuning
 
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