1995 Chevy k1500 z71 4wd pickup with a 5.7L (350CI) Throttle Body Injected automatic with 126,000 miles. A while back I had bad misfiring (sputter, missing, and stumble) while accelerating and in the last gear under greater load i.E. Going up a hill (truck would shake and stumble) but not much while idling (slightly if at all) Replaced plugs (two plugs and ash deposits and one plug had oil on it) and fuel filter (filter poured out brown gasoline) and it ran like a champ for about a week.
Started doing the same thing again and also missing more at idle. Replaced wires, distributor cap, and rotor button. Wires had arcing spots, distributor cap was corroded and worn, rotor button was rusted onto the distributor and had lots of black deposits, the circular metal plate where the cap screws down on was solid green with corrosion, removed as much as possible but unable to remove it all. Solved the problem and ran wonderfully for a couple weeks to a month.
Now it is miss firing again while idle (worse than before) and while accelerating and cruising in last gear under load i.E. Going up a hill EXACTLY as before. Hoping it's not a warped or burned valve, especially since it ran like a champ for a while after every repair.
(As a side note, kind of unrelated, after the wires and distributor cap and rotor button, I had the intake manifold gasket replaced for leaking, valve cover gaskets replaced for good measure, and driver side exhaust manifold replaced because of a crack, done by a shop. The mis firing started a week or two after these repairs)
No black or blue smoke.
Stumped, any help would be greatly appreciated, Thanks in advance!
P.S. After replacing wires, the plastic clips unavoidably broke, some of the wires are touching metal brackets connected to the block, and I caught a couple wires touching the block, so I tied them back out of the way with zip ties. Should I wrap them in plastic electrical lume where ever they contact the metal brackets to prevent arcing?
Tuesday, February 8th, 2011 AT 4:02 PM