Low rpm misfire... need opinions.
10-27-2013, 10:20 PM
#1
10 Second Club
Thread Starter
Low rpm misfire... need opinions. I've got a heads/cam car and for a while now (pretty much since I done the first heads/cam swap 2 years ago) I've had a 2k-2800k rpm misfire occasionally. Its always been very light and only in the that rpm window and seems to be throttle position dependent but it seems to be a little worse now. I always just thought it was the nature of the beast type thing since it was so light. When the car does it I can give it a little more fuel and it will clear out. The plugs and wires probably have less than 2k miles on them and I'm not getting any codes at all. The car traps 126, M6 SBE car so I don't think the misfire is anything crazy wrong since it runs so strong. Its just irritating. Anybody have any ideas on what it could be and not throw a code?
10-28-2013, 07:30 AM
#3
10 Second Club
Thread Starter
I actually replaced the TPS all ready. It was definitely bad because their was a lot of slack in and out and it didn't spring back anymore. It made no difference though.
11-04-2013, 09:05 AM
#5
10 Second Club
Thread Starter
The car started it after the heads/cam and I done a mail order tune at the same time. After that I had the car dyno tuned and the problem stayed. Its actually been tuned twice by two different tuners and the problem stayed it just seems to be a little worse now than before. I've watched STFTs with a scan tool. At idle they start around -3 and will climb to the low teens as it idles a few seconds. I never really watched driving because I honestly don't know what I'm looking for. On the wideband when the misfire occurs it doesn't seem to change. Some times it'll happen in the 11s sometimes it'll happen in the 15s. It really just depends on how much throttle I'm giving it when it happens.
