That cat may be plugged.

Not sure how my reply got ahead of your post!

 

hey guys, im brand new z28 owner, loved em for years, finally got one. but.... its got issuies. its a 4/95 LT1. itll turn over a few revolutions, then get hung up, just like a dead battery right when it gets near a compression stroke. did that for a while, burnt up the starter, new starter, new battery, it does the same thing. itll get past it, but its slow. it will eventually start, but you have to get the idle up past 1k. it revs up fine, but you can hear valves clatter if you rev it up rapidly. it will stay running for 5 or 10 minutes no problem, then if it idles, it stalls, you try to restart, and the starter struggles again, play with it a while, it might start, runs like crap, stalls. i tried bypassing the ignition switch and jumped the starter with no ignition on, and it never had that hang up spot with the starter, i thought it might be a fuel issue if it was dumping fuel in a cylinder, i pulled the fuel rail and injectors and they arent leaking and appear to be firing properly. at one point, i had it running no more than 10 minutes and the cat was glowing red, thought it might be a timing issue, supposedly the previous owner replaced the distributor, so i replaced the module, still runs the same, i cant read codes, it was an obdII but its a 95 and the scanner wont connect with it, fuel pump was replaced, and flter, and one o2 sensor, i got a regulator ready to install.... what next? i was gonna check the timing, but theres no markings, it kinda seems like it runs ok when its cold start, but havent definitely narrowed that down yet... thanks alot for any help.

 

Your car uses an OBDI computer but the test port is configured for OBDII. You need an OBDI scanner with a cord that fits the OBDII connector, or a scanner that can reads both OBDI and OBDII.