gearhead90

ok i just started doin the final tweaks to my LT1.

1994 z28
503/510 comp cam
1.6 full rollers
new stock lifters
same push rods(checked)
pacesetter long tube headers w/ O2 sensors(brand new)
EGR delete w/ back off plates
air pump delete

i got it started but seems to be runnin like it has a miss in the motor somewhere. i have been tinkerin with the rockers for about 2 days now and still seems to runnin the same way..i ran the motor at 1500RPMS for about 10-15min like i was told so that the computer can catch up with the over-sized cam..i have never messed with the full roller rockers but have the general idea on how they work.. i looked at the tailpipe when it was runnin and seems to be sprayin a little bit of fuel out.
i think thats all i have to say thats on top of my head about it that i can think of..is there any advice someone can give me to help me with this problem?

my1994z28

Did you have the pcm tuned for the cam yet?

Injuneer

Are your Pacesetters cera-metallic coated? Often, it seems that the burn-off from the coating will contaminate the O2 sensors (which you indicate are brand new). Generally, its better to run your old sensors for a couple weeks.

Are you sure you don't have some plug wires burning on the headers? Misfires cause the engine to run rich, which causes even more misfires.

As asked in the first response above, has the PCM been tuned for the cam? Running the engine at 1,500 RPM isn't going to help the PCM learn anything. It needs to be programmed first. Then is needs to be driven UNDER LOAD over a wide range of RPM and throttle positions.

gearhead90

no my PCM has not been tuned....and i dont know how to tune my PCM...and my headers r not ceramic coated....so how do i tune my PCM?

raulz28

you can get a mail order tune from pcmforless, madz28, or a dyno tune from a performance shop in your area that knows about these engines

RamAir95TA

If you expect it to run even halfway decent, you need to have it tuned, no bones about it. I recommend going with www.pcmforless.com