ok here i go. i just recently had to replace head gaskets on my 2000 blazer 4.3 L. After finishing it ran fine for about a day. though I did keep getting error code p1345, which I understand is due to I had replaced CPS and need to do a case relearn. Anyway, was driving home fro work and truck started to run rough. Then it started to run really rough. When I got home checked and found that PCv valve elbow had broken . So I replaced that as well. No it still runs rough and makes a tapping noise from right side. I can smell strong smell of fuel but can see no leak. the engine is actually jumping around while running. I am no expert by anymeans and am sort of learn as I go. So any help or suggestions are appreciated.

 

Did you read through the steps in this post?
P1345 Explained

 

okay so i looked in my Chilton manual and determined that distibuter is installed incorrectly. i can not get the rotor to line up with the embossed # 6 on distributor. how do I get this to happen and get distributor to seat properly.

 

If the distributor won't seat properly when jumping the timing between the cam and the distributor, you need to rotate the oil pump drive shaft down inside the block. A long screw driver or an oil pump priming tool are needed to accomplish this.

Once you get that squared away, the thread below will shed some further light on getting the distributor timed correctly:
EDI Engine Timing