Rough Idle

my 3.1 v6 grand prix 2001 seems to have a rough idle. when ya listen to the exauhst it has a slightly louder puff every now and then, and when your sitting in the car you can sometimes feel a little jerk here and there. I was led to believe that it might be a slight vacume leak or small missfire in one of the cylinders, or is it just common, cause my grandfathers 3.1 buick, 1999 century seems to do the same thing roughly.

On the GM 3100 Vin "J" and 3400 Vin "E" 60 degree engines you may have some minor roughness at idle. Could be cause for alarm or maybe not. Also, it may vary if the A/C is on or off. These engines react to the type, brand and heat range spark plugs you install. How old are your spark plugs and if replaced what brand? Also, the ignition wires...ever replaced and what brand if so.

They are Bocsh(however you spell it) double platinum, just replaced them at 110,000 miles and i got 123,000 now. Ignition wires or module has never been replaced. yea i dont think its a big deal, but i wanted to make sure

GP's and Bosch plugs don't get along. Bnaylor and I have promised to stop beating up on Bosch plugs, but.......... :evillol:

Did we? I forgot...:lol:

His plug wires are due and the best plugs to use are the OEM AC Delco platinums 41-940 which was specifically for the 3100/3400 engines. The AC Delco Iridium 41-101 and NGK TR55IX Iridium are too generic in nature and made for a wide range of GM engines. People complain about idle issues when using them.

it just got worse, now the service engine light is on, and it smells like burnt rubber under the hood, the idle now is so rough that you bounce in the seat, so tomarrow im hooking my little Computer up to it, and gonna see if its a possible missfire due to the plugs, could be a MAF cause i have seen that before for the same problem, also those little vacume leaks!!!

Run the scanner and get the DTC codes. Post them. You've had this problem on and off for awhile now. On the MAF sensor, the one for the 3100 engine is very reliable but it is a possibility. Remove the air intake ducting. Clean the MAF input screen and the MAF wire elements with MAF spray cleaner. The CRC brand is good stuff.