On a 94 5.2 1500 you have to let it warm up for 30 min. before driving. In that time it will run very bad, backfire through the exhaust, and is very rich and then after 30 min. it will run perfect. If you let it sit more than 2 hrs. then you must go through the whole process again. If you drive it before it's ready all it will do is skip very bad and backfire the the exhaust and throttle body. This thing has new timing set, TPS, CPS, CTS, coil, computer,muffler, cat. was cleaned out and a few other things that I can't think of right now.

 

Where did you get your cps, and ckps from? These motors really don't care for the aftermarket sensors.......

 

Did you replace the o2 sensor as well?

 

^Exactly what I was thinking zman....

A bad pre-cat 02 sensor could be causing that trouble....prolly reading weird, making the PCM dump in fuel...

 

Aftermarket

 

Yes, but did it again today. So I guess I'll know in the morning if that fixed it. It does sound better.

 

Just tried it again. And the same problem. coud this be a bad throttle body?

 

^Could be cap/rotor or the IAC motor...

 

Cap & rotor has been replaced since this has started, and replaced the IAC motor lastnight and still the same.

 

Finally fixed, the aftermarket CPS was bad. NO MORE AFTERMARKET, it cost in exsess of $2000.