pearl_iroc

hey guys

well this isnt for my car but my bros 89 5.7 TPI Iroc. he took off the plenum and runners to clean/port when he put everything back together the car doesnt run right. basically it has a hard time starting when it does it backfires through the intake, loud poping noises, also if you he the gas just a lil bit the rpm will jump to 2500 hold and slowly drop down, mean while under the hood there u can hear like a loud banging noise from the drivers side number one cylinder, from my searching on here it sounds like the timing is off (i cheched the distributor cap and its tight so i dont really think it moved i cant even budge it if i try to turn it), but would this also explain y the rpm jumps and stutters like that? we changed the plugs they were all black, checked and re checked the firing order, fuel pressure is 45 i adjusted the TPS havnt touched the IAC (not sure if i should) also about adjusting the timing i was reading there are 2 bolts that hold it but i only see one ?

anybody got any other ideas?

thanks

AkitaMan

Is the ses light on?

pearl_iroc

ooops should have mentioned that there are no ses lights

bmxerboi221

My 2.8 did the same thing, it was either the TPS, EGR, or wrongly adjusted valves. I think i did all three about the same time so i dont remember which one it was. Maybe that will help

pearl_iroc

thanks for your input bmxerboi221, we ended up cleaning out the iac and settining the timing and it seems to have stopped the problem