rough idle puffing exhaust

[college man]

The computer is subtracting fuel for a rich condition. try doing a_x000D_
power balance test. do it both ways. spark and fuel. is this symptom_x000D_
at idle or driving? car at operating temp? does the car have a MAF sensor?_x000D_
if so clean it with maf cleaner your not

Topic

[moparfan]

this is a common issue on GM vehicles. normally being a ruptured diaphragm. here is a video to help you test that. http://www.youtube.com/watch?v=AKtR_yF7bi8

[Matt]

Do you have access to a scan tool that will show live data?

[austind3d]

The car now has high fuel trim and gets better at high rpms maf .31 map 11 it has no codes but sounds like it has a random misfire

[rice400]

I agree with collegeman, try

[moparfan]

Quoted From austind3d: _x000D_
_x000D_
The car now has high fuel trim and gets better at high rpms maf .31 map 11 it has no codes but sounds like it has a random misfire

_x000D_
_x000D_
that sure changes things. do a power balance test to see if you can

[dreamer2355]

If the fuel trim numbers are on the positive side and start to decline as you accelerate at per se WOT, then you have a vacuum leak._x000D_
_x000D_
A scan tool with PID data would be helpful here._x000D_
_x000D_
I would also do a coolant pressure test too.

[EricTheCarGuy]

Great posts above but I wouldn’t rule out an ignition issue, if your plugs are old you might consider changing them, I’d use AC delco’s personally.

[Author]

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