Engine problems -Temperature related
 

I have a 1990 C4 L98 with some engine issues. Any suggestions would
be welcome. The problems seem to be temperature related. When the
engine is cold, or the air temperature relatively cool, say below 75
degrees, the engine generally runs fine. On hotter days, or after the
engine has run for a while to get nice and hot, the engine loses power
and runs very rough. At idle, the engine RPM oscillates up and down
by a few hundred RPM when hot. Also, if I let the engine idle in my
driveway for 15 minutes or so, it starts to over heat. That could
just be a thermostat.

I recently replaced the EGR valve, and I still sometimes get a code 32
after a half hour of highway driving. The old EGR valve was clearly
stuck open. Is there a sensor, like a temp sensor or O2 sensor that I
should be looking for? Any ideas?

Engine problems -Temperature related
 

"SteveC" > wrote in message
...
>I have a 1990 C4 L98 with some engine issues. Any suggestions would
> be welcome. The problems seem to be temperature related. When the
> engine is cold, or the air temperature relatively cool, say below 75
> degrees, the engine generally runs fine. On hotter days, or after
> the
> engine has run for a while to get nice and hot, the engine loses
> power
> and runs very rough. At idle, the engine RPM oscillates up and down
> by a few hundred RPM when hot. Also, if I let the engine idle in my
> driveway for 15 minutes or so, it starts to over heat. That could
> just be a thermostat.
>
> I recently replaced the EGR valve, and I still sometimes get a code
> 32
> after a half hour of highway driving. The old EGR valve was clearly
> stuck open. Is there a sensor, like a temp sensor or O2 sensor that
> I
> should be looking for? Any ideas?

It's a bottom feeder and tends to vacuum up all sorts of trash, clean
it out of the front of the radiator.

Engine problems -Temperature related
 

On Aug 2, 2:57*pm, SteveC > wrote:
> I have a 1990 C4 L98 with some engine issues. *Any suggestions would
> be welcome. *The problems seem to be temperature related. *When the
> engine is cold, or the air temperature relatively cool, say below 75
> degrees, the engine generally runs fine. *On hotter days, or after the
> engine has run for a while to get nice and hot, the engine loses power
> and runs very rough. *At idle, the engine RPM oscillates up and down
> by a few hundred RPM when hot. *Also, if I let the engine idle in my
> driveway for 15 minutes or so, it starts to over heat. *That could
> just be a thermostat.
>
> I recently replaced the EGR valve, and I still sometimes get a code 32
> after a half hour of highway driving. *The old EGR valve was clearly
> stuck open. *Is there a sensor, like a temp sensor or O2 sensor that I
> should be looking for? *Any ideas?

I think I found the gremlin. I replaced the spark plug wires and now
I can't stop the engine from running like it's brand new. The idle
has improved, as well as exceleration, etc.