Losing power on hills

1984 G-20 with 305, auto, fac. air, 90,000 miles.

Was crusing the interstate the other day when I started losing power on a hill. A slight hill at that.

The truck then died. It restarted after about one minute and ran normally but slowed down going up every hill and would die if the hill was too long.

Top speed during this time was about 20 mph until it quit.

It ran great downhill and pretty good on level ground. As soon as an incline came it slowed and eventually quit.

I am checking vacuume leaks now and the carb seems to have no sticking parts.

The air temp valve in the air cleaner is not holding vaccume. Should it? Anyplace else to look?

Idcelr8

Check for lose of fuel or good hot blue spark.
How is fuel pressure?

I had a similar problem with my 1988 G Van with a 305, it was gradual over time, it ended up that my Catalytic Converter was plugged up.

Fixed the converter and now she's flying along great.

Regards.

I tried and tried to get it to start. It would run for a bit on starter spray but would always die.

I got my son to cut out the cat converter. It took a few times to get it to start (it has been sitting for a month or so) but now it runs like it always did.

He put in an aftermarket cat and all is well!

The cat that was on it was the orginal and it was clogged solid.

Thanks so much for your input on this. It is good to have the old workhorse running again.

Sam

Thanks for posting back how it went.
Glad you got it going.
But remember if the cat was clogged up something usually causes that.
Go over you tune up end real good.
Running rich or engine miss is the no one cause of clogged cats.
Good Luck

Thanks for posting back how it went.
Glad you got it going.
But remember if the cat was clogged up something usually causes that.
Go over you tune up end real good.
Running rich or engine miss is the no one cause of clogged cats.
Good Luck
While I agree that often there is a cause, those old-style GM pellet - type converters were not particularly efficient for flow.

A rich mixture can cause the converter to overheat and melt internally. However, there is a good chance your converter simply became clogged due to accumulated rust and carbon, so there may be nothing wrong with your mixture. . If you still have it, cut it open and take a look.

I had the same problem but it ended up being my fuel filter. I replaced the fuel filter and ended up replacing the tank becasue the van had sat un used for almost three years the rust had built up to the point that it was either change the tank or the fuel filter every 5 miles.