454 FPR on 350.. now misfire on cyl 5

[jessezipper]

1998 z71 silverado 5.7, auto... i bought it and the PO stated he put 2500 running gear and drive train on it...

so it was having symptoms while driving of a bad fuel pressure regulator.. i bought the one for a 350, installed it and no start,did a little looking online and noticed the one i pulled off match one from a 454. so i got a new FPR for a 454, installed it and now it started right up... it didnt have a misfire before i tore into it,now i have a misfire at cylinder 5 ...

i put a spark tester on it and it fires, new plug, and even swapped spark plug wires and still misfire at cylinder 5...

 

[michael hurd]

The misfire could be anything from a rocker arm issue ( IE: no lift ) to a cylinder with no compression. Pull a compression test to see what you get and start there.

 

[SAATR]

As I said in your other thread, move the injector to another cylinder and see if the misfire follows it. If it does, you found your problem. If not, michael has you lined out.

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