An interesting thing about the internet... I have been involved with support
groups for most of the cars I've owned from SE-Rs to X1/9s to Merkur
Scorpios, but I can't find a support group for my Suburban, so, I figured
this group probably has the highest percentage of GM Pickup/SUV owners than
any of the others I know about.
I have a 95 Suburban 1500 (5.7 gas, throttle body injected) with 97k miles
on it. It's been running fine, but recently has started idling rough. When
you give it gas, it doesn't stumble or hesitate at all. If I take it out of
gear the idle speed goes up to about 800rpm (from 550 or so in gear) and the
idle smooths out. The engine has never stalled, etc. I can't see an idle
speed adjustment to bump the idle up to 600 rpm or so, besides that,
something happened to make it start idling rough. Fixes so far: replaced
spark plug wire, they weren't replaced last time I tuned it up, so I did
that. I've also replaced the PCV valve. I've checked the rest of the vaccuum
lines off of the TBI and none of them seem to be leaking (remove the line
and plug it and the idle speed isn't affected). Brakes are working fine, so
it's not a vaccuum leak there. Tonight I'm going to put new spark plugs, cap
and rotor on it. The thing I just thought of is the oxygen sensor, but that
wouldn't make it idle rough)
I have a possibly related problem. After driving on the highway for an hour
or so, all of the A/C flaps close (compressor running, fan running). The
rear A/C continues to work fine. Aren't the flaps all vaccuum controlled?
Could that be related?
Any ideas?
----
John Steczkowski
Director of Engineering, Server I/O
Crossroads Systems, Inc.
512-928-7242
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