89 p.u. chugging while warming up

[facial]

Hi all,
I have an 1989 2wd, manual transmission
P.U. with the 22R motor.
Recently I've noticed when the truck is between cold and fully warmed up it has a chugging or missing problem. The truck starts fine but once the temp. gauge starts to move up passed the white line, and when I run the engine at the higher range of 2nd or 3rd gear, It starts to chug and miss. Once the p.u. is fully warm it appears to go away.
I've replaced the fuel filter and cleaned the carb. inside and out with cleaner but it still chugs and misses. Any ideas what may be causing this????

Thanks

[laxer49]

I had a similar problem with the 22R. What I can suggest is to check the auxiliary accelerator pump (AAP). Basically, if you can figure out where to vacuum line attached to the AAP, take a small piece of hose, (detach the current hose) attach a small piece of hose, and try sucking through it. If you get a mouth of gasoline, you need to replace the AAP diaphram. Should be 3 screws - but be careful because the diaphram is sping loaded - not high tension - but just be sure you put it back the way it was.