I posted a while back about a surging problem. I have since found and replaced a bad distributor cap, fuel filter. I even changed thefuel pump (because the test gauge was more than a pump). It's still surging while driving down the road, but not while at idle?? When I run her up to 1500-2000 she will run even, then surge up a bit and back down.This car ran perfect for two years, and I am perplexed on how something could happen without any obvious sign? I have an edelbrock 600 on there, could there be someting internal wrong? Could the coil cause this type of upsurge?

 

Did your car sit for a long time?
Did you notice any (new) vacuum leaks when you had it running?
How is the gas in the tank? Is it old?
Do you use a fuel stabilizer?
Your carb may need cleaning - gum, varnish or dirt may be the culprit.
Is the carb bolted down securly? - no leaks around the base. Get some carb cleaner and spray around the base while it's running and see if the idle changes. You could also use a spray bottle with water and spray around the vacuum lines, intake manifold, etc. to help look for any vacuum leaks too - again, see if the idle changes.

Check it over and let me know.

-Stefan

 

The car was driven every week, including the day it started surging. I don't see any vac leaks, and the gas is fresh, usually relaced every two weeks. No stab\ilizer, and I tried brakeclean around the carb base and along the edges of the intake and no rpm change. It idles fine, and acts up while above 1500 or so. It just started out of the blue. Do I have to take the carb off to clean, or just dump something into the tank??

 

Check vacuum advance.

 

It has an MSD ignition that has no vac advance.

 

Is surging where the engine revs higher on its own? If so, is it only reving higher and not bottoming out?

 

It idles fine....when I run it up to 1500 rpm, it will start out to besteady, then bump up to 1600 or so and then back down to 1500. It never goesdown below where it starts out at. I also posted again because I was looking down the carb while reving it up higher, and the gas was not "spraying" in, it was more like larger drops "raining" down into the carb?? Not sure whats normal. Carb is an edelbrock 600 tha is 3 years old and trouble free until this point.

 

I think you've got some dirt in the squirters (don't know the real name). It should shoot a stream. You can get a rebuild kit for about $45 from AutoZone or O'reilly. The kit is number 1477 and is very easy to do. Buy some carb cleaner too.