So here's the deal. I just finished replacing the head gaskets and got it all together. Before the gaskets blew, the truck was working fine, so when I did the work, i left the carb alone along and did my best to replace the distributor exactly where it was when it quit.

The truck runs now, no leaks, no bad noises, and stays cool. However, I can't seem to get it to idle smoothly! I've spent a few painful hours trying to get it running and can't seem to figure it out. At idle, the engine surges significantly from about 2000 rpm to stalling or nearly staling. Since I left the carb alone, I figured it would be close to where it needs to be adjustment wise. The vacuum lines are all where they were as well.

So, is this a vacuum problem? Im wondering if the EGR diaphragm behind the carb is not sealing and causing a huge vacuum leak? My brake booster seems to work ok, so maybe its not a leak? The only other thing I can think of is the timing, but I am fairly certain it is very close to where it was before (I don't have a timing light or else I would have checked for certain).

If you have any ideas that would help me so much! The EGR valve is $63 so I don't really want to replace it unless I know thats the problem.

Is is the carb? timing? vacuum? electronic choke? something else?

Thanks!!

 

While many people can "tune by ear", it's still helpful at times to use the proper tools to make sure everything is setup and adjusted according to Hoyle. Otherwise we might start chasing our tail and "fixing" the wrong thing or compensating for defects somewhere else without realizing it.

Mechanic's vacuum gauge and a timing light are your friend here. Till you can get your hands on them make sure the distributor wasn't installed "a tooth off" and whatnot.

 

Use vice grips to pinch shut the hoses going to vacuum accessories to rule them out or find your problem. Loosen distributor and rotate it a little in either direction while running to see if you can make it happier.

Also: you gotta wonder why/how you blew (both?) head gaskets

 

Tedster9, you're probably right, I will try to get my hands on those tools and verify that the timing is on and that I do or do not have a vacuum problem to set a baseline and build off that.

I did pull the EGR valve, block off the ports with a gasket and reinstall it to see if there was any difference. Nothing changed, so I am ruling the EGR out.

In response to why the head gasket blew (just the passenger, but I replaced both), I am not 100% sure. However, it is probably a combination of 3 things I identified. 1, I tested the thermostat and it was not functioning correctly. I do have an aftermarket temp gauge that I never saw go above 220 (when it blew was the only time it rose that high, usually it runs right around 200). 2, the gaskets on that thing have to be really old. I don't know how old, but it could've been 20 years or so. 3, I have probably been pushing the old motor a little more than I should as I've done more highway driving recently than I have before. Its just a 4 speed tranny and the engine is not built for high rpms. So, that's my best guess as to why it blew a gasket, but oh did it go!