99 Malibu with random cylinder misfire.

[pd_cobb]

I have a 99 Malibu 3.1 and it picked up a bad misfire. First I checked alt. and test showed 2 vlots so I changed that. Then changed all 6 plugs and wires. Bought a new coil (all ohm'd within speck) but tried it anyway on each but still the misfire. I put the code checker on it cause of the check engine light that showed the whole time of prob. Codes were: 106- map sensor.
113- IAT sensor
300- random/multiple cylinder misfire.
I have changed the map sensor also and tried but still same misfire. I also changed the fuel filter too. I checked the connectors and wires, all seem ok and output good as per book. Where else can I look for this misfire prob. It acts like a plug missing on a normal run and at idle it's like 2 cylinders not there. Will start fine but I do have a odd smell out the tail pipe. Not like a flooded gas smell but different. Water and oil is fine and don't use. Ideas??
Paul

[pd_cobb]

I have now added an ignition module and now have the check engine light satisfied but still have the miss. Really could use some heads up on this...I'm out of ideas.
Paul

[bcopeland]

I had a cylinder misfire that new spark plug wires fixed in my 99 3.1

[pd_cobb]

Originally Posted by bcopeland

I had a cylinder misfire that new spark plug wires fixed in my 99 3.1

As stated above...been there done that but still skip. All codes were cleared and one still hangs in and its PO107. Again above chg. MAP sensor but now found out that 2 other sensors will throw same code error. MAF sensor (I know where that is) and VAF sensor. Thats all the codes. Car starts ok but rough idle and drive because of skip. Will these items I just mentioned cause the skip? Mechanically the car is good I guess but sounds like a rocker arm or lifter tappin cause of skip. Didn't have this at all or even made any signs of those probs. Someone with knowledge of those sensors I listed please let me know of them. Thanks

[wymi]

Do you know what cylinder(s) are misfiring? How about unplugging one sparkplug at a time then start the engine and see if anything changes. This is how I would start looking for the problem, find out which cylinder is not firing and then track from there. I had a bit of a rough idle and I cleaned my MAF sensor with spray electrical contact cleaner and the idle is very smooth now. BTW, I believe my MAFS got so dirty and black from the K&N filter that did not filter very well, I don't recommend using them. If you are going to clean your MAF sensor be sure not to touch any of the small wires with anything at all, just get some electrical contact spray and spray everthing until clean and let it air dry, don't wipe or touch it at all!