Originally Posted by f1_mimmo
Back in Feb my 05 GC 3.7 (55K miles) started misfiring. Didnt have a code reader at the time so i dont know what codes were showing. Took it to the DLR and they "changed" 2x O2 sensors. Ran fine till May then the light was back on w/ the same misfiring. Took it back to the DLR and they changed the other O2 sensor. Ran fine until this Friday night, lights back on and thing is misfiring again. What i noticed this time was if get the revs up past 5K you can feel a surge and the misfire goes away. This time i went out and bought a code reader, i'm getting p304 (misfire #4 cyl). I bought a new plug, coil pack and 2 cans of B12 and 1 can Seafoam. Put 1 can of B12 in the tank and ran both B12 and Seafoam thru the brake booster line. The lights off now and i keep the code reader plugged in while driving. It did start misfiring at idle for a minute or so but went back to a normal idle, apparenty not enough to trigger a code.
Anyone exeperince this? Do the 3.7's suffer carbon buildup issues ? If so is there anything better to use other than B12 and Seafoam.
Thats funny bro. I bought my 05 3.7 with 56k on it and it had that miss. Changed a couple of o2 sensors, didnt help. Today i bought all new spark plugs,, hopefully that will fix it. Let me know if you figure out the problem before me. I also ran a Full Throttle fuel system cleaner through the brake booster and it didn't help much. Later.