I just drained about 2 gallons of water from my gas tank...filled tank with premium fuel and runs better but won't completely run 100 percent ....7 cylinders....what else can I check?

 

Engines don't run too good on water! Amazing it runs at all! Did you purge the water out of your fuel lines and change your fuel filter? An easy way to find a dead cylinder is to run the engine for about 20 or 30 seconds, then feel for a cold exhaust port at the manifold! If it's water in a injector, it may clear itself out as the engine runs, but then again, maybe not.

Did the drain hose under your fuel filler door get clogged?

 

Disconnect the plug wires one at a time. The one that doesn't change RPM/engine note is the dead cylinder.

 

then pull the plug out, and plug it back into the spark plug wire. hold with rubber glove, or like me with pliers wrapped in black tape around jaws, have bud/wife crank engine, if you can see a spark (might be hard to see if it is bright out) then you have narrowed your problem to a non-firing fuel injector. Ohm test it and see if it matches the other injectors. if it does, its probably the harness that is the problem, not letting signal through to that injector. its more likely the injector itself than the harness, the ohm test will show if that is true.

it is possible to replace only one injector, but people here will not sanction it. but if you are absolutely strapped, i have heard of it being done. you can order 1 injector from jon at fuel injector connection for 50$ or a full rebuilt set for 190. its doable. you can send your injectors away to jon at fuel injector connection, or, if you are on a budget like me, clean them youself for 25$. here is what i did. i used jb weld overnight on the cap instead of his plastic welding method.

i observed no leakdown, no dripping, and very similar spray pattern against a cardboard box. this will not tell you flow rates. jon at fic is much better than this if you have the money. i didn't.

you can verify your harness is firing the injector plug (by getting a 29$ noid light set, i just bought a set and they are sooo easy to use, worth the money if yiou need to verify your injectors). http://www.princessauto.com/en/detai...et/A-p8014007e


you can also ohm and continuity test your spark plug wires if you suspect they are trashed. obviously, before doing anything with your spark plugs and wires, pull your neg bat cable. cheers. be safe. these guys on this board have saved my bacon, and my $$ so many times!