leek157

ok its an 87 iroc l98 all stock, just put new plugs , msd cap, rotor, coil and wires on it, and its worse than before, before with the old stuff it was misfiring and being slow now its worse. i had it hooked up to scopes and a whole bunch of other computer stuff at school and i cant figure it ou, it seems all the plugs are firing correctly, so then i checked for vaccum leaks.. none, then i checked the injectors i did a resistance check and they all came out around the same a little higher than spec but they are 21 years old and all about the same, and they were all opening and closing, i could not get a pulse width on them due to the rubber covering on the injector harness so i could not back probe them, so i decided to hook it up to a motorvac and run the injector cleaner on it for about 45 minutes, it runs smooth, but its still misfiring every once in a while and its running slow as hell i cant even spin the tires on wet pavement, this car used to chirp the tires in 3rd. does anybody have an idea what is going on, o yea i also checked the iac pcv but couldnt get to the egr. any help would be GREATLY appreciated. thank you

Darkshot

iTrader: (4)

Possibly fuel filter? Its cheap and easy, might as well give it a shot. If it doesn't work it probably needed it anyway.

kowboy59

iTrader: (8)

I am having pretty much the same problem. My car will idle perfect, but once i drive it, it bogs down bad like it only has 8* of base timing and thats it. Even when I rev it up it only maxes out at 4500rpm

Could a bad ecu or chip cause this issue?

I have a whole new distributor, plugs, coil and all new fuel system.

I cannot figure this out at all. ALl ican think of is that teh plugs are a little loose and thats the issue.

leek157

ive got a new fuel filter in it, and ive also got all new wires plugs cap rotor and coil and you can feel and hear the motor missing and all the wires are plugged up, i cant figure it out at all

leek157

my car will idle fine sometimes a rough start but once under a load it sucks it takes more time to get to 60 flooring it than normal accelerating

ladyjynx

It might seem silly but you can try checking your air filter. Also a vacuum leak can do it. Might not help but worth a shot.

leek157

air filters are also brand new , there was a slight vaccum leak near the purge control solenoid but i took care of that

darkride86T/A

This is a long shot, but have you checked your MAF sensor?

ljnowell

what about fuel pressure?

ladyjynx

How is your timing and fuel pressure?

leek157

pressure is good timing is the only thing i havent checked yet, i have to pick up a timing light

kowboy59

iTrader: (8)

Well for me let me go through all my new stuff. NEw maf, walbro fuel pump, 48psi at wot and 40 at idle, summit distributor with 8* of base timing, msd coil ngk tr6 plugs, old msd wires which i hope is my issue, 24# venom injectors, and a holley Stealth Ram.

Car idles like a champ but has or seems to have no spark advance. I really think my computer is shot.

enoughtraction

samll block chevys often need timing chains at a little over 100k miles (110/120) youl notice an ok idle and when you punch it it might bog down and then maybe pick up or you might be able to get it to pick up pumping the gas... anyway its worth a check if youve exhausted everything else I recomend using a true roller dual chain if you beat on it and dont want to do the job again. cheers

ljnowell

A timing chain being old and sloppy will not cause those kind of problems, nothing requiring pumping the gas pedal. Generally the composite teeth come off. That gives a real quick car doesnt run effect though. If the car runs, its probably nothing to do with the timing chain and gears.

leek157

im thinking my egr may be stuck or something causing a huge vacuum leak

enoughtraction

on most chevy timing issues the plastic gear strips right off but if that doesnt happen even chains can get slop like a timing belt does and you have valve and ignition timing issues due to it that can be hard to track down i had it happen in a c10 pickup I had all kinds of power loss issues and i wasnt able to set the ignition timing right i ****ed with it allot then i installed a true roller because it was hitting 130 without dieing yet and all my power loss disapeared... maybe a fluke but if hes tried everything else a $50 timing chain kit isnt a huge investment....