LS2 misses and backfires when warmed up
LS2 misses and backfires when warmed up Got a LS2 swapped into my 67 Camaro. Been running it in the garage (idle) while I have been working on other things. It has started and idled fine from day 1. Today I pulled it out the garage trying to see if I could get the fans to come on since it was finally warming up outside. It sat in the driveway idling for ~20 mins waiting for the temp to get up for the fans to kick on, when it got to about 210 it started missing and backfiring really bad. It stalled when I tried backing it into the garage, seemed to be running very rich. I let it cool off and it ran fine again. What could be the cause of this? Its a stock LS2 with long tube headers, stock tune. Thanks in advance!
TECH Addict
Joined: Aug 2005
Posts: 2,305
Likes: 126
From: Monroe,NY
Could be 02 sensors or coils not working correctly when they get hot. Do you have a maf on this setup? Does your coolant temp sensor work going back to the computer? Do you have the IAT sensor working correctly? If you could find someone near by with tuning software they can scan it for you. There are a lot of possibilities.
With open headers, the O2 sensors are sensing a very large exhaust leak. Then the fuel trims go way positive, causing a very rich AFR. When the exhaust pipes are installed, the fuel trims will be correct.
Russ Kemp
Russ Kemp
