94 truck 4cyl manual
sea level, no problem. engine cold (high idle), no problem. 5k feet, engine warm, try to go from stop, engine will stall unless i rev it. at 8k feet it's even worse. especially bad if inclined of course. my suspicions are air mass sensor or exhaust sensor. neither have ever been replaced. i have emissions test results (but not with me now). i tried to remove the exhaust sensor but the nuts are blobs of rust at this point, which i guess is normal. haven't tried the torch yet.

 

How many miles on your engine ??

Is the check engine light on??

Air filter in good shape ??

Is this EFI or carb??

I have been over most all the passes with my 22re Celica with no problems.

Maybe you have something else going on.

Running the fuel tank below 1/4 tank all the time ??

 

More information on your vehicle would help.

could definitely be a lot of things but if this is a fuel injected vehicle I would start with the normal tune up stuff (plugs, dist cap, testing the 02 sensor, fuel filter, etc) also try to test the TPS as well. You shouldn't need any real adjustment going from 0-5000 feet.

 

EFI, 282k miles, already checked air filter and i definitely would have mentioned check engine light, which has never occurred. this has only been a problem for a year or so.

 

What about every thing else we suggested you check?
have you tried to pull codes to see if any are stored?
what is your timing set at?