I have a 2.8 with the feedback Varajet carb, and wanted to see if anyone had any advice. I'm at my wit's end with this, and if I can't fix it, I'll probably have to send it to the junk yard.

After throwing some inexpensive parts at it, I finally broke down and took it to a reputable shop I've used in the past. After 2 days, the mechanic couldn't figure it out and told me to take it to a GM dealer. He didn't charge me a penny, and warned me though that the dealer would just start throwing parts at it. I have had bad luck in the past when it comes to taking a car this old to a dealership.

I figured since it would be a $100 just to have the dealer open the hood, it might make more sense to just try to throw some cheap parts at it myself.

The car wants to stall at just off idle and sometimes does, if you slowly accelerate from a light, like a bog. It almost has a mild "bucking" feeling when you accelerate from a light. If the car is placed in park while idling (fully warmed up), it will stall out after about a minute. The idle rpm is about 700.

I don't think it's the tranny, because it does this in neutral also. When cruising, the car smooths out considerably, but there is still a mild "tugging and releasing "sensation.

I replaced nearly all the vacuum lines, and the transmission vacuum modulator, and on my vacuum gauge the car pulled around 21 inches at idle, so I don't think there is a vacuum leak.

I have replaced the mechanical fuel pump, fuel filter, PCV valve and EGR valve. The carburetor is a remanufactured unit that only has about 8k miles on it. It has a newer cap rotor, plugs and wires. It also has a new coil. The cat converter is only about 2 years old. I even replaced the battery because it was older and I thought it might be messing with the ECM because of insufficient voltage. About the only thing I have left to check is the distributor module, which I plan to test.

The car is not throwing any codes.

The car is worth very little, it's worth a lot more to me to have a running vehicle than a few hundred dollars from a junk yard.

My only other option is to get a non-feedback carb and distributor from a early 80's Blazer, and bypass all the computer junk. I'm wondering if my problem is with some mixture solenoid or idle sensor on the carb. I think it would be easier and cheaper to just sidestep all of this with a mechanical carburetor that doesn't have all of these sensors. I just don't want to spend a couple hundred bucks doing this, and the car still doesn't run properly.

Any help you could give me would be greatly appreciated.

Thanks again

 

I don't have any idea but you might be better off in tech/engine so the big brains are more likely to see it.

 

Thanks for the tip, I'll post it over there also.

 

Sure been awhile since I played with a carb?..but maybe I can send you in the right direction,maybe not?.Anyhow..from what you stated I would lean towards the power enrichment circuit in the carb.Just because its remanufactured doesnt mean its working.I an't familar with that particular carb,but usually when a accelerator pump goes bad ,it doesnt supply the engine with additional fuel ,so when you stomp on it...it sends very little fuel or none into the combustion chamber..giving you a major dead spot or stall,feathering it out from a stop usually helps but not when you want to pass someone.So I dont know if that carb has a accelerator pump? but would make sure you have good fuel pressure,the float level is within specs.If the float is set too high it wont supply enough fuel to the accelerator pump circuit..hence the lean dead spot.When you sit idling and it stalls ,it sounds like its running out of fuel?..if the car was sitting for a good period of time,its a good chance the fuel line is blocked..giving you a restriction.I like those glass fuel filters for checking that?.You also could have what is called vapor lock..where the fuel in the bowl is boiling and starving the engine.If it runs fine till it warms this would be a good place to look?..Make sure the carb base gasket is a good thick one (insulated) Good luck ..thats a lot of info ,but kinda hard to fix things without seeing the car?..

 

I had a similar problem w/my 2.8, it had a leak in the fuel line. Is worth checking