No engine power!

I have a 86 K5 Blazer. Six years ago put a new gm 350 a rebuilt trans. and had all the work performed for inspection. Truck was run once or twice over the years. This winter I got it on the road to push snow. I ran the blazer once for about 12 hours pushing snow, on the way home I thought I had a problem with the trans. Took the k5 out today 2/20 to pick up my kid at a neighbors house. Started out fine but at the large steep hill my k5 lost power. I pulled over to check the blazer over. It was idling fine but when I would rev the engine it was muffled. I drove up the rest of the hill (barely)
and picked up my kid. On the way back I was quickly throttling the gas pedal which seemed to give little bursts of power. I am thinking that I have an airflow problem. Any Thoughts?

When was the last time you changed the fuel filter? Is it injected or carbureted?

I would guess the fuel filter was changed when I put the new engine 5-6 years ago. I do not if it is injected or carbureted. I now that it has the big old round air filter on the top of the engine and that in 86 It had a mess of tubes around fuel injector or carburetor to meet CA emissions. As far as fuel: I had a 1/4 of a tank for 5-6 years and have only filled it once before I used it for the 12 hours.

"As far as fuel: I had a 1/4 of a tank for 5-6 years and have only filled it once before I used it for the 12 hours. "

Ouch. All of that varnish in the fuel tank didn’t do anything a bit of good. Gasoline does go bad after a while. Everything is probably gummed up with it. Change the fuel filter at the very least a run a concentrated bit of fuel system cleaner through it - Chevron Techron or Seafoam. You might get lucky with that.

I’d also pull that air filter and off and clean the rodent nest out of it.

Big problems? I was a little worried about the old gas. How bad could it BE?

5 Minutes later. Just check No rodent nest, clean air filter but maybe a little smell of bad fuel.

“How bad could it BE?”

How bad could drinking rancid milk be?

Actually, drinking rancid milk is probably better in the sense that you don’t have to do anything but live with the physical effects while your body works it out.

The blazer will likely be more work. Think of dismantling the fuel system.

First I’d replace the fuel filter. Then I’d get one bottle of seafoam and one of techron. I’d dump the seafoam in now, and run the truck as well as you can until you’re down to maybe 1/8 tank. Then I’d dump the Techron right into the 1/8 tank and drive it to almost empty. Full it up and see where things stand. If it doesn’t help, at most you’ll be out about $10 or $15.

And don’t forget to check the air filter & housing.

But you should also inspect the ignition stuff - spark plugs, wires, and distributor cap. All of that sitting didn’t do those any good either.

Point taken even though I don’t drink milk. So where DO I start in the engine or with the fuel tank.
any body know where the fuel filter is on this auto? Also it does not seem that any you think it is airflow related?

Thank you all for your help

I will be going with your suggestions. I love the medicine cures. I used that lucas trans syrup to fix three different trannys. One had a leak, leak fixed one had a leak and solenoid problem all fixed.

You can pick up a basic repair manual for this blazer at an auto parts store for about $20. It will probably do you some good.

A fresh, full tank of gas and a new fuel filter would be a start. If this is carbureted, you may want to take the top off the carburetor and see if there’s any gunk in there. If fuel injected, a couple of cans of Techron would likely help.

“As far as fuel: I had a 1/4 of a tank for 5-6 years and have only filled it once before I used it for the 12 hours.”

This is not good news…Today’s cat-cracked gasoline will turn to varnish over that length of time and can cause major problems. Everything gets plugged up and is very difficult to clean…

A TBI injection system LOOKS similar to a carb except there are two injectors sitting on top pointing down and they both have a wiring connector…There is an electric fuel pump located inside the gas tank. You can hear it run for a few seconds when you turn the key on. A carb will have an engine driven fuel pump and the filter located inside the fuel inlet to the carb…