Misfiring Cylinder

rmajewski1

I just recently purchased a 1997 GMC Yukon with 50,000 miles on it. Since the day I bought it, it has had a recurring problem. Most of the time it drives great, but sometimes it starts chugging when I slow down to stop for a light or when I start accelerating. The "Service Engine Soon" light also comes on. The dealership tells me that the computer says it is a "Misfire on cylinder #5," but they don't know what to do about it. They can't pinpoint the problem. It could be any number of things. To me, if the mechanic was worth his salt, he would be able to figure out the problem. Anyone's advice on this problem would be greatly appreciated.

122169

I own a '97 K1500 Suburban with 60,000 miles on it. I have had to replace the 'in the tank' electrical fuel pump three times in the last 15 months. The symptoms start with one or more cylinders having a lean misfire. Which is temporarily solved by a spark plug replacement. Within a few hundred miles the misfire returns. This continues until check engine light comes on. Trouble code eventually shows low fuel pressure, leading to the pump being replaced. Has anybody else had this problem. The dealer has been little help other than to take my money.

alcan

Has the fuel filter been replaced? Nothing will kill a fuel pump faster than a restricted filter.

122169

Yes. the fuel filter was replaced with each pump replacement.

oilcan2

try changing the spark plug wires with stock GM
wires or a good set of aftermarket wires.if you
can find out if the spark plugs were changed at
all that would also help.if somehow you could
connect a timing light to #5 and get it to a
place where you could close the hood and drive car
with the timing light in place you could simulate
your problem look at the light and see if #5 is
actually missing.