Stumbling, missing at low rpm, surging at cruise?????

[OkieFishMan]

So my timing issue has been fixed by the new distributor. It was shot!

But my engine is still somewhat stumbling and missing a bit at low rpm, and is surging at cruise on level ground. Could it be the ol slobberjet needs rebuilt?? Maybe throw an edelbrock on it?? Truck ran great for the first 400-500 miles but has since started to go down hill. Has new distributor, cap, coil, wires, plugs, vacuum lines, and fuel filter. I'm at a loss. I kinda think carb, but not sure.

The truck at hand is the truck in my signature, and it was used very sporadically the previous several years before I got it in May. Help!!!!

 

[Honky Kong jr]

So my timing issue has been fixed by the new distributor. It was shot!

But my engine is still somewhat stumbling and missing a bit at low rpm, and is surging at cruise on level ground. Could it be the ol slobberjet needs rebuilt?? Maybe throw an edelbrock on it?? Truck ran great for the first 400-500 miles but has since started to go down hill. Has new distributor, cap, coil, wires, plugs, vacuum lines, and fuel filter. I'm at a loss. I kinda think carb, but not sure.

The truck at hand is the truck in my signature, and it was used very sporadically the previous several years before I got it in May. Help!!!!

It could possibly be sucking crap off the bottom of the tank. An wide band is so helpful for these situations. Old school guys need to get over the fact the the rivers use them.lol they are invaluable in diagnosing drivability issues carb or fi. Did you check the stone filter in the slobberjet? And eww Eddy carb. I had one I was gonna make a how to tune an Eddy carb video using a 5lb hammer. Lol if your gonna be looking for mileage and smooth operation you may want to look into injection plenty of options out there.

 

[OkieFishMan]

If I clean out and rebuild the quadrajet, can I add an additional filter to stop some of the junk, if that solves my problem? Or am I stuck cleaning out the tanks right now? EFI is not in the budget at this time.

 

[OkieFishMan]

Update: I determined it is the carb. I'm having the carb rebuilt and an additional aftermarket fuel filter installed and see if that fixes the crappy idle and surging. Truck goes in next Tuesday. I will post back once it is done.

 

[Honky Kong jr]

Update: I determined it is the carb. I'm having the carb rebuilt and an additional aftermarket fuel filter installed and see if that fixes the crappy idle and surging. Truck goes in next Tuesday. I will post back once I it is done.

 

[1987 GMC Jimmy]

Before you take it in there, are they reputable? I wouldn't trust a Quadrajet with any shop, any big name rebuilder that sells in stores and online stores, and few carb specific places. I sent mine off in the mail to be rebuilt and was very happy with the results. I used Mountain Man Carburetor in Hackett, AR for mine, and Quadrajet Power also has a good rep. He's on here, too, by the way. They'll put a primary throttle shaft bushing in if it's a sloppy high mileage unit, make it look real nice, and rebuild/tune to the exact specs. The only thing you'll ever need to adjust is the curb idle mixture. Not trying to plug anything here, but I think ****** rebuilds are a large contributor to the bad things that people think and say about Quadrajets.

 

[OkieFishMan]

Before you take it in there, are they reputable? I wouldn't trust a Quadrajet with any shop, any big name rebuilder that sells in stores and online stores, and few carb specific places. I sent mine off in the mail to be rebuilt and was very happy with the results. I used Mountain Man Carburetor in Hackett, AR for mine, and Quadrajet Power also has a good rep. He's on here, too, by the way. They'll put a primary throttle shaft bushing in if it's a sloppy high mileage unit, make it look real nice, and rebuild/tune to the exact specs. The only thing you'll ever need to adjust is the curb idle mixture. Not trying to plug anything here, but I think ****** rebuilds are a large contributor to the bad things that people think and say about Quadrajets.

Yeah, the guy I'm using is THE local quadrajet nut, along with his dad. He is a mechanic by trade, and he and his dad bracket race for fun, and use nothing but quadrajets. He loves them. His dad is magical with them. But I totally agree with you, a lot of guys don't know jack about them.

 

[1987 GMC Jimmy]

Sounds good, then. Hopefully that'll get you going good and quickly, too, since it's local.

 

[OkieFishMan]

Sounds good, then. Hopefully that'll get you going good and quickly, too, since it's local.

I hope so. I'm ready to hook on to the fifth wheel on Labor Day weekend and give this thing a tow test!