First post, I've read hours of previous postings. My 95 GC limited 5.2 started knocking under load. It got worse as I drove it. Then it wouldn't run at all. I replaced; plugs, wires, cap, rotor, spark coil, MAP sensor, and CPS. I reset the computer by grounding the positive cable. I pulled the valve covers and spark wire and turned it over. Lots of oil flow, rocker arms and valves appeared to function properly and quietly. CPS was the last replaced part. It will run smoothly at idle and as long as it's in park. Revved up to 3400 rpm with no problem. On the street, any load (e.g. uphill) and it knocks and loses power. I'm afraid to make it worse if I drive it. What else could be causing this??

 

You need to test fuel pressure while under load, also the timing chain stretching and throwing your timing off is a common issue on the Magnum engines.

 

Thank you. I did test fuel pressure, it is at 41 psi, top of the range. Does a stretched timing chain equal a rebuild or junk and start over?

 

Welcome to the forum.

Has the spark plug wiring TSB been implemented?

 

Thank you. The wire set I bought, Duralast actually, has plenty of slack to keep the wires from aligning. I did crawl under while it was running and realized just how bad the seam leaks were on the muffler. I had already replaced the cat so I bought a new exhaust and muffler. Project for tomorrow, hopefully not Saturday. I read in another thread a couple of weeks ago (best I can do for attribution) that if there isn't enough back pressure the timing will be off. If that was remembered correctly and is true, this might be the final piece of the puzzle. I will let you all know'

 

Sorry, no I haven't implemented this particular alignment. However, the wires are in arcs and cross at almost 90 degrees

 

No, just install a new timing chain and gear set.

 

This reply shows the Miller 6635 tool for locating the timing cover to be concentric to the crankshaft.

 

Oooooooooooooooooo! That doesn't sound fun at all.

 

Well, I did the exhaust pipe, muffler and cat job today. She's running pretty good. Still a bit of knock on strong acceleration but I did reset the computer. Ran her around the neighborhood and she's already smoother. Only 48 1/2 more miles to go to finish re-training. I'm in CO at about 6k feet. We shall see