I have a 92 GMC k1500 Suburban 5.7L with 208K on it, it has started running
very poorly, it starts very very hard when cold and will not idle until I
run it at a fast idle for 10 to 15 seconds, it seems to not have near as
much power as it did. When it is warm and started it will not idle and when
you get it in gear and take off it will surge really bad for a minute or two
before it runs smoothly again, it does not do this every time however. It
has set code 44 many times since this started (lean exaust), I have replaced
the O2 sensor and put new plugs in it. Anyone have any idea what I might be
Check the bolts on the throttle body, make sure it is tight to the intake
manifold. Also check all of the vacuum lines and make sure the EGR valve is
Ok, I had a similar problem in my suburban and the dealer replaced the tbi
to manifold gasket. They said they thought it was sealing when it warmed up
and when cold everything contracted breaking the seal...this was on a 91
which should be the exact drivetrain. Thanks for the help I appreciate it.
quick test: take one of those 'heater hose clamp-off' type vice grips and
clamp down on the return line while watching the O2 sensor readings and
injector pulse width on a scan tool
you will see (at idle) the IPW return to around 1.2 mS and O2 go from
'lean' to switching back and forth from rich to lean if the pump is on its
I always try and finish the job first then double up on the beer to make up
for lost time. Yep, the tank was empty, in fact I ran out of gas on my way
to the shop where I worked on it, a friend of mine has a nice shop with a
lift so that made the job much easier.
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