89stdcab4x4

i have and 89 p/u with a 22 re, newer motor (around 110k). the head has been rebuilt, along with head gasket, water pump, timing chain, cap, rotor, plugs, wires, belts, alt, radiator and hoses. it has a cel for knock sensor and tps idle switch. the problem it stumbles, bogs and misses at low rpm's only under load. it idles fine, and once its moving it goes goes fine. there is no tach in the truck so im assuming between 1000 and 2000 rpm's is when it happens. it usually only happens once the truck is warmed up. i have talked to a few people that tell me it is completely different things. such as, fuel pump, fuel injectors clogged, or coil. i have little money to fix it and cannot afford to just aimlessly replace parts. i hope someone successfully fixed things problem before and the its something simple like vacuum lines.

thank you

Georgiadave

You have Check engine light codes for the knock sensor and the TPS switch. So you are going to find the cause of your problem in one of those systems. The codes just tell you where to look, not that any specific component is faulty. Study the factory service manual on the sticky for trouble shooting these systems, and you will solve your problem, perhaps for very little cost.

abecedarian

the throttle position sensor can affect engine operation similar to what you're describing. 4Crawler, another member here on yotatech has a write up on how to check it. http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml
i would check and adjust the tps first, then worry about the knock sensor, which is likely either not installed or connected, or a problem with the wire.

89stdcab4x4

thanks for the info. i just find it strange that i've had this truck for over a year with both codes, and this has started recently