Power loss with aggressive acceleration

[Brownie82C10]

My 1982 Chevy C10 (six-cylinder engine) is old and tired. The engine doesn't stall with aggressive acceleration from a start, but there is a very noticeable drop in power. The truck accelerates fine — cold or warm — as long as I ease through all the gears (with automatic transmission) and don't push the pedal to the metal.

It's been a number of years since all the plugs, wires and distributor cap were changed.

Where should I begin with an engine analysis?

Thank you.

 

[fast 99]

sounds like a possible lean condition fuel supply or carb

 

[Edelbrock]

Might be using up the fuel in the carb faster than it can be replenished. A way to test, would be to to fill the car through the vent and then pin it to win it. If that solves the problems at first, but the problem returns, then I would clean the carb and replace the fuel filters. Also, try removing the gas cap as a test, in case the vent is partially plugged. If you have a manual choke, that may also help diagnose the issue.

 

[Brownie82C10]

Thank you, Edelbrock and fast 99. I did replace the gas cap about a year ago. If I recall correctly, I started noticing the issue not too long afterward. Also, I park my truck in my garage nightly. (It's my daily driver.) Gasoline fumes are noticeable, but there's no signs of a fuel leak.

 

[Brownie82C10]

Well, the problem doesn't seem to be related to the gas cap. I swapped it out with no change. I even drove home from work once with the cap off. The hesitation when I floor the pedal persists. This usually is in first and second gear. Once I've gotten into third gear and up to speed, there's no hesitation when I speed up.

 

[75gmck25]

What type of carburetor is on the 6 cylinder?

When a 4 barrel has this type of symptom you would usually check to make sure the secondaries are working and properly kicking in, but I thought the 6 cylinder used a two barrel carburetor. The other items to check is the float level and the fuel filter. It may just be running short of fuel.

 

[Brownie82C10]

It's a two-barrel carb, 75gmck25.

 

[Edelbrock]

You can get a brand new carb for under $100 with free next day shipping.
Then you could bolt it on and see if that solves the problem.
If the problem is fixed, keep the carb.
If the problem remains, return the carb free of charge.

They can be found on Amazon.

 

[Brownie82C10]

Thank you, Edelbrock.

 

[Camar068]

You can get a brand new carb for under $100 with free next day shipping.
Then you could bolt it on and see if that solves the problem.
If the problem is fixed, keep the carb.
If the problem remains, return the carb free of charge.

They can be found on Amazon.

Items that can not be returned: "Products that may pose potential health and safety risks once sold"

Good luck returning it. I'm glad they have that in there to help crutch the abusers. When throwing parts at something, I don't expect my money back unless the OEM (edit: or parts store) says it will fix it. I consider those parts as spares.

Karma is a b|tch.....it'll get you in the end.

 

[Ricko1966]

Thank you, Edelbrock.

That's horrible advice. That's the kinda crap hack mechanics do. Let's just change parts until something works. Well changing parts at random, makes actual diagnoses harder. And installing parts then returning parts,costs the seller money,which he passes along to all of us in the form of higher prices. Any carb you can get new for 100.00 Goodluck with that being any good right out of the box.

 

[Ricko1966]

Things to check,first because it's free and easy. Take off the air cleaner lid, look down the throat of the carbureator and snap the throttle open with one hand,you should see a squirt of fuel,just like a squirt gun shot, don't see one or a weak one,sounds like an accelerator pump problem. Can you make it stumble in park by stepping on the throttle too fast? If you can again with the air cleaner lid off,blip the throttle by hand,can you make it accelerate better by cupping your hand over the throttle opening? If so it's lean and we need to find out why. Spray carb cleaner around the carbureator base and where the manifold bolts to the head. If the idle increases you've found a vacuum leak. One more free test,wait until dark and spray the spark plug wires and distributor cap with salt water out of a spray bottle,look for lightning. Post what you find.