Ok heavy thinkers need some input, searched til blue in the face and have some ideas on what the problems could be but want different ideas.

1995 Blazer- Put a crank kit in last year, along with full tune up, ran beatiful for several months then, hard to crank, strong gas smell, put a FPR on and sloved that problem back to running good. I know, I Know should have replaced whole CPI, but didn't know better at the time. Some time later power slowly started to decrease, heard rattling under car, replaced CAT, got power back but exhuast frequently stinks but still running good ( idle just a tad rough). Here's where I'm stumped. Put a timing light on it and HB indicator was jumping all over the place, pulled distirbutor and it was completely worn out, put a new one in along with a new TPS. Car ran and idled better than it ever has. Then it happened, start it up cold or hot and it continueosly hunts for idle, park or drive, still or moving. You might get in it another time and it doesn't do it at all, it will run like a new motor. Its very inconsistant. Couple of days ago put in a new IAC, cleaned EGR, no change. Last night after 1 hours worth of driving it ran the worst I've ever witnessed, surgeing about 300 or 400 rpm's. This morning it was like someone parked a different car in the driveway, absolutely no problems. Idle was steady right from start up and went down the road smooth as glass......

After searching the forum it seems that I need to start with the CPI unit but if it or the nut kit is bad wouldn't it run like crap all of the time ? or do I have a sensor crapping out thats half working. CEL works and it has no codes

 

Does it surge up or down in RPM?

 

It seems to always surge up, especially driving down the road.

 

Just an update, if you don't come back and update, searching the forum is useless. I found lots of good threads but they ended nowhere.....

Problem solved !!! Car ran so bad today it threw a code, p0122 (TPS). I had just replaced the TPS with a brand new one from Advance Auto parts that evidently was a POS right off the shelf. Went somewhere else and got a GOOD tps, car is running better than ever. Special thanks to Advance Auto and China for screwing around with me....