1996 4.3L misses, surges, and knocks intermittently
 

Howdy all, I searched some of the threads, and I'm sure the answer is here somewhere, but here goes:

We had some problems with the motor cutting out when going from cruise to FWD idle last season. Motor would restart fine, and run fine in neutral idle and and fast idle, but again cut out intermittenly at FWD idle.

When I winterized it, I changed all the spark plugs, and for giggles checked the compression, all where 180.

This season, first run out was great. No problems. Today, took it out, tubed with the kids for awhile, then fished for awhile. On our cruise back to port, it began to miss, knock, and surge while at high cruise, and again at FWD idle. Shut it off, it restarted fine, ran smooth while in neutral and through neutral RPM's. Tried it again at 4500 RPM, and again surging, sputtering, and occasional knocking. Brought it back to 3000 RPM for the rest of the way back. Still surging, but no knocking.

Thinking maybe fuel system?? Thoughts? Thanks all.

Re: 1996 4.3L misses, surges, and knocks intermittently
 

In case someone stumbles upon this post, I believe I found the problem: water in the gas. I believe the gas cap seal was rotten and/or the fuel vent did not have a "P" loop in it allowing water to get in the tank.