Acceleration and Stalling Problem 72 GMC

[Killer Bee]

need a little more engine, ignition, carb, etc. info to make any suggestions here..

and do yourself a favor, pick one thing at a time to adjust / replace or you'll end up in circles..

and agree with above, trans shop should have some idea what they may have done to affect those symptoms..

they must have had some comments regarding drivability during their test drive..

based on these circumstances, I was thinking;

• cracked distributor cap or cocked out of position
• any plug wires pulled may have been crossed, check 18436572
• distributor hold down may be loose or have loosened in the shop
• vacuum modulator hose damaged or some other large vacuum leak

posting some basic specs, what you know or can prove by testing, and what you've done would help..

good luck!

[ncpetersc]

Subscribing to this, as I feel I've had similar experiences. My opinion is worth next to nothing, but the first thing I thought was not firing on all 8 as others have suggested.

My truck is the same year, and I am pretty sure my fuel tank is gunked up. I have a quadrajet and the filter in the carb inlet had rust colored debris in it.

GOOD LUCK!

[geezer#99]

Originally Posted by ncpetersc

Subscribing to this, as I feel I've had similar experiences. My opinion is worth next to nothing, but the first thing I thought was not firing on all 8 as others have suggested.

My truck is the same year, and I am pretty sure my fuel tank is gunked up. I have a quadrajet and the filter in the carb inlet had rust colored debris in it.

GOOD LUCK!

Did your filter look like this?
If so, likely nothing wrong with it.
https://quadrajetparts.com/sintered-...lter-p-80.html

[ncpetersc]

Originally Posted by geezer#99

Did your filter look like this?
If so, likely nothing wrong with it.
https://quadrajetparts.com/sintered-...lter-p-80.html

It definitely wasn't the bronze type.. it looked more like this

https://quadrajetparts.com/short-pap...lter-p-78.html

[Stocker]

Originally Posted by ncpetersc

It definitely wasn't the bronze type.. it looked more like this

https://quadrajetparts.com/short-pap...lter-p-78.html

I recently had one of those completely plug up (age? fuel? beats me). I had installed it when I couldn't find a bronze one.
Now I'm back to a bronze filter and I will never buy another pleated paper filter for my Q-jet.

[Thatguywithaneye]

Update:

Turns out it was a mixture of a few things.
1)Did an HEI Conversion because the points looked terrible
2)Had the carb rebuilt (super dirty and gummy)
3)The gas was so bad it was terrible so currently trying to dilute the old stuff with some fresh stuff.

A combination of these makes the truck start and run like its 1972. Never really realized how much power it had until it was all fixed.

Next step...wiring

Thanks for everyone's help and suggestions.

[Thatguywithaneye]

Originally Posted by Killer Bee

need a little more engine, ignition, carb, etc. info to make any suggestions here..

and do yourself a favor, pick one thing at a time to adjust / replace or you'll end up in circles..

and agree with above, trans shop should have some idea what they may have done to affect those symptoms..

they must have had some comments regarding drivability during their test drive..

based on these circumstances, I was thinking;

• cracked distributor cap or cocked out of position
• any plug wires pulled may have been crossed, check 18436572
• distributor hold down may be loose or have loosened in the shop
• vacuum modulator hose damaged or some other large vacuum leak

posting some basic specs, what you know or can prove by testing, and what you've done would help..

good luck!

Thanks for the ideas. So it has the Chevy 350 engine (stock). The carb is the Rochester Quadrajet. I'm unsure of the ignition, but I would imagine it would be stock as most of the truck is.

I have done very little to the truck. I've done things like change the fuel filter, Air filter, Make sure everything is tight and connected. But as I stated before I'm just learning about this stuff.

I checked the distributor cap and it seems to be in good condition and all wires were connected. I didn't check to see if there were any in the wrong spot, but would it even drive at all if they were in the wrong order?

So here's the thing about the vacuum line. When I was replacing the fuel filter it was obviously in the way so I disconnected it and as I tugged on it it just fell off. It took pretty much no effort at all. When I went to go put it back on it barely would stay on. So the line only had about an eighth of an inch of area to go into the hole on the carb before it hit the rubber on the vacuum line. I'm not sure if that makes any sense, but I can post a photo for clarification.

If you have anymore questions I will happily answer them so I can have it running smoothly.