pinning and knocking on hills

[kv8950]

i have an 89 2.6 4x4 with 144,000km when i reach a steep hill on the highway i experience a rapid power loss and the engine starts to knock and increase in temp. but it only does it at highway speeds. im thinking it might be my carb but im not sure. any ideas?

[abeemanator]

From my experince with this it sounds as you are running too lean, Have you ever noticed the exhaust manifold actually glowing red after you drive up a steep hill? My 1984 Toyota did that alot, and I tracked it down to being too small of a main and secondary jet, it had a weber though, if your truck is still stock you may have a vacuum leak, you may have a plugged passage in the carb and it may need cleaning, or you have the float level set too low.

[camoit]

vacuum leak, timing may be off, intake manifold loose, carb float level may be to low or has a blocked passage.

[pennyman1]

Don't forget to change out the fuel filter, and check the fuel pump as it could be going out starving the truck for fuel. Also check the hoses in the box on the drivers fender - there are vacuum hoses in there that split or mice chew on and lean out the truck.

[Acuta73]

My bet is vacuum, particularly if it cuts out the engine at all. Or if it starts cutting out.

Took me years and multiple mechanics to find out my head was cracked in such a way as to create a direct vacuum leak but not break the water jacket (a compression test woulda found it, but no one thought of it). Same issue, only did it when the engine was warm and at Interstate speeds. I assume the crack got a touch wider under those conditions, just making it even harder to nail down.

Rest of the ideas are certainly valid, and may be it. Just placing my wager. LOL