sciff5

iTrader: (1)

Hey guys I'm getting some slight backfires near idle in my ls1 swapped rx7. It usually only does it at low rpm whether I'm cruising or idling but its most prominent at idle it will pop slightly.

when the car first starts the idle is high and the engine seems pretty smooth then as it warms up it tries to bring the idle down from 1200 and as it slowly drops around 1050 the popping becomes more prominent and the car idles rougher and then the pcm kicks up the idle back up to around 1100 and it goes away and then it tries to bring the idle back down but it never goes below 1000, maybe 980 990. I am reading the rpm using a scan gauge straight from the pcm so I know its accurate.

I pulled the plugs after the car was only running a couple hours (total time on the plugs) and they were black

The guy working on my car I know was running it without O2s before I had the exhaust on.

I am guessing it was running rich

ENgine isnt pulling any codes

sciff5

iTrader: (1)

I am gonna try some cheap plugs. Anyone have any suggestions on what I should use from autozone that will be a good replacement for the tr55s

dca1042

fit some o2 sensors,it will be a place to start.
i just had same problem with a car this week.
cheers dave

sciff5

iTrader: (1)

It has o2s now and like I said its not pulling any codes, so I'm assuming they are still good but I could be wrong.

kmracer

iTrader: (1)

stock cam or what?

sciff5

iTrader: (1)

stock cam. Just longtubes with true dual 3" all the way back and sweet thunder resonators and a ported tb

fast400

iTrader: (1)

sciff5
You ever get it figured out?