Engine shaking at idle
#1
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I am a little baffled at what is happening with my 2000 Trans Am M6. Gas mileage is still good at 22-24mpg average but the SES light will come on for a couple days and then turn itself off for a couple days. It usually turns on after a long decel from the toll road up to a redlight (70mph). Sometimes the engine almost shuts off at the signal, the rpm drops to about 200 then it picks back up and idles. This turns the SES light on. Also, it idles rough now and the shifter handle shakes a lot. The car does not have a miss at any rpm other than idle. It has started detonating (on 93 octane) at WOT around 5000 rpm when I tested it so I let off. It NEVER used to do this.
Where do I start? We pulled the codes and all I had was a "cat efficiency" code. I don't think a bad cat will make an engine idle rough.
I have some Mopar fogging foam and I think I am going to try that today and clean the MAF. Any other ideas?
Thanks!
Where do I start? We pulled the codes and all I had was a "cat efficiency" code. I don't think a bad cat will make an engine idle rough.
I have some Mopar fogging foam and I think I am going to try that today and clean the MAF. Any other ideas?
Thanks!
#3
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exactly what he said, lol, dont ya get the shakes when you "backed up"? lol if the computer is telling ya something is wrong, you might as well start there, plus a good excuse for an upgrade
#6
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Well I did the MCCC and just did the test ride to burn it off after letting it sit for 3 hours. I must say it runs a LOT better and idles smoother. It also doesn't try to die after decel to a stop with the clutch in. I did find a loose PCV valve hose that needs to be replaced but that's tomorrow. I am going to go ahead and install the truck fixed orifice pcv valve as well.
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#8
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It's getting a "cat-mod" right now and new O2's. At 70,000 miles I don't feel that is a waste of money if it helps. I'll need sims now or is it cheaper to tune it out of the PCM?
#9
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Look in to a tune they will delete the codes at the same time. Lots of people say a bolt on tune is not worth it but it helped my milage out and smoothed out my rough idle. Frost on here does mail order tunes pretty cheap search his name