Hi,I recently purchased a '97 Sierra SLT,Z-71,with a 5.7 liter v-8,automatic
trans.It runs like a raped ape when it's warmed up,but if it sets for a few
days in the garage,it stumbles and shakes till it gets warm.If I start it
every day,it starts and runs just fine.When it sets too long,it sets codes
translating to #1 cyl. misfire or #5 cyl. misfire,although I know there's
more than one cyl.misfiring.It also has a strong smell of fuel when it does
this.I cear the codes and it never lights the "service engine soon" light
untill it sets for a period of time again.Any thoughts as to a cause and a
cure?
Thanks for any comments~~~~~Ed

The most likely cause of your problem is:

Leaking injectors, leaking slowly. Long term, meaning several days of
sitting, allows the injector in the ports of the cylinders setting codes. To
leak down enough to flood the cylinder temporarily, causing the miss.

If it's the Vortec injection system. It will need a cleaning. Any other
injector might be cured by a cleaning, but the Vortec I think are covered by
a special GM warranty. You'd have to ask Ian or Doc for the specifics on
that.

I hope this helps?

Refinish King


"DesertEd" <theraus2 (AT) cox (DOT) net> wrote

"DesertEd" <theraus2 (AT) cox (DOT) net> wrote

Let it sit for a few days, then pull 8 eight plugs BEFORE firing it up.
Whatever is in the cylinder should be on the plugs at that point, beit fuel,
coolant or tons of oil. You'll be able to smell the fuel or coolant even if
it isn't on the plug, and you'll be able to see the oil. Pay special
attention to the cylinders that are misfiring.

Just becuase you smell gas doesn't mean there is too much fuel in the
cylinder. If it's missing for other reasons all that unburnt fuel, no
matter how much or how little will end up coming out the exhaust.

Doc