OK, I have been fighting this issue for 2 months now. Last month, I pulled plugs 1,3,5,7, they were fouled out. 2,4,6,8, were clean. So, I replaced the Opti. I also did new MSD 8.5 wires, MSD coil and NGK TR-55's. This fixed the problem for @ 20-30 miles. Car started missing and backfiring again so, I pulled plugs 1,3,5,7 and they were fouled but 2,4,6,8 were clean. I replaced the o2 sensor with a bosch ( the pass. side already was replaced by previous owner with a Bosch). I also replaced the plugs again on the driver side with new TR-55's. Car ran great, but it flashed a SES light after 10 min. of driving (@ 5 miles). The next day, car had no SES light and car ran great (only drove 5-8 miles). Day three, car started out good, no SES but the miss slowing came back after 10-14 miles and slowly started to backfire until I got it home. Pulled 1,3,5,7 and again, fouled (black as coal) 2,4,6,8 very nice clean burn. I don' t know what else to do. The car is a 97, LE stage 2 package, longtubes, no cats, PCM for LESS programming and OBD 1 convertion. I checked all the wires, no burns and no crossed wires (They are atleast 1" away from headers. Also, I used no dielectric compound (heard bad things about that stuff). Guys, any more suggestions would be greatly appreciated. Thanks a bunch, Troy.

 

I am guessing....

A vacum leak that affects just one bank....

Air entering the exhaust (from the emissions air valves?) and the puter thinks is too lean and pumps it full of more fuel... till the spark plugs foul up.
thats why new plugs work great till the get fouled up.

Also... a ruptured Fuel Presure valve? I heard it dumps extra fuel into the intake manifold....(this theory does not explain why only one bank is rich)

A Stuck open or clogged Fuel injector... either sending too much fuel (leaking) or non at all.. causing a lean misfire... sending all the air into the exhaust and fooling the 02/s into thinking its too lean...making the PCM pump it full of GAS


well thats all I can think of for now.

Marvin

 

I don't have any emmisions, air pump is removed and the headers have no emission checkvalves. I checked the very few vaccum hoses that I can see. Are there any behind the motor? Thanks for the help.

 

ttt

 

did this start happening after you installed the heads and cam package? Does the LE2 come with the dowel pin already cut? If the dowle pin on the cam is too long, it'll cause the opti to sit lopsided, and destroy the opti. just a suggestion...

 

The LE pack was already on for 12,000 miles before problem