Help with Troubleshooting

[Bart's Z34]

Can anyone tell me what my symptoms would be if my EGR Valve is sticking. sound anything like this?
Currently as the engine warmes up, it seems to have no power to go and it seems to happen only on cold days. The RPMs won't go above 3000 (very slow to get there) and I can hardly make 30mph. I was thinking it may be the carb but i checked it today when it happened and the choke is fully open. I need help!!!!!

85 Blazer
2.8 Carb

[gectek]

maybe the cat...

[rx191]

sounds like a cat, un bolt teh exaust and drive it up the street real quick that will tell you for sure in about 5 min

[Bart's Z34]

cat was removed years ago. any other ideas.

[bszopi]

Since it only happens on cold days, it might have something to do with condensation in the fuel lines freezing up and limiting the fuel available to the carb. I would take a look at the fuel system components and see if there could be anything causing a restriction (filter, lines, etc).

[rx191]

how does it run on normal days and does the, engine run better after it warms up? it could be the carb,

[tractorman]

I'd look closer at that choke. Also, if it has that stupidass "heat stove" setup that lots of vehicles from way back when had, make sure that that flap in the air cleaner pipe isn't sticking shut, or the heat stove hose isn't collapsed.

[Bart's Z34]

It only happens when it warms up (about 10 - 15 min after starting). If I stop when it happens and shut the engine off for 5 min it runs ok. That made me think about a vacuum issue (time for something to bleed off). I will check the breather flap tonight after the truck cools off. Another thing I was reading about was the EFE (Heat grid under carb), Haynes says if it is not shutting off the hot air/fuel mix will cause the engine to run like it was out of tune. Something else I will check when it gets cold. I may have to carry my meter with me and when the problem happens again take the readings from the EFE and temp sensor and then check and see if the air cleaner flap is open or closed as well. Thanks for the ideas, I think we are going in the right direction. I will let you know what the results are.

[Bart's Z34]

ok. carb is rebuilt and have been driving for the past week. we had a couple of cold days and i have not had any trouble so far (knock on wood). the float bowl was pretty skuzzy, a lot of dirt in the bottom, i think i am going to put a second filter near the fuel tank too help keep the dirt out. i also had to replace the secondary chock pull off and a couple of vacuum lines needed replacing. the thermostat for the EFE heater was shot, so i replaced it. it's been running good (knock on wood, again), now i am going to concentrate on the 3.4 swap. i will keep updates on that.