'88 Isuzu Trooper II idling problems

Ok, I kind of think this is a vacuum leak problem, but I read the fuel mixture would run rich.

So I found some vacuum leaks, so I may need new hoses. I kind of fixed those up, at least in a temporary fashion. I don't hear much of a hiss anymore. The engine seemed to do better but...

I came to a point where the engine would surge in RPM like when you hit the gas pedal, then it would go down, up and down, up and down. Like you are just sitting there pumping the gas. This is at idle. At this time the fuel mixture seems to be rich and smoke is coming out of the tail pipe. More than usual.

I did note what looks like a antifreeze leak near the throttle body, about where I would expect the thermostat to be.

What do you think?

Oh yeah, I did add a whole thing of fuel system cleaner in a few gallons of gas. But, it ran stupid before this. But, maybe this explains the extra smoke.

It started running weird right after I was trying to tighten a belt by moving the pully with a crow bar. Coincidence? I don't know if I was prying on that part of the vehicle though. It is an aging vehicle so dry rotted seals might not be that unusual.

Troy

[edit on 21-8-2008 by cybertroy]

Check the ect resistance, make sure it's not open otherwise the computer will compensate for extremely cold conditions, also unplug the iac motor and see if the engine idles differently.

Ok, thanks. I bought new vacuum hose. I'll replace that and see what happens. I'll check on those things if the problems persist. I need to fix that coolant leak too.

Troy

Well, I have some extra information.

The engine does not seem to surge when it's cold, but it starts surging when it has warmed up.

I put some new vacuum lines on the most obvious problem areas.

Troy