4X4 that dont like to pull it weight

[steelhorserider0891]

hears the deal i have a 91 4.3 w/ 205,000 miles it has had a complete tune up, and i believe i have got every one of the sensors replced now w/ the exception of the egr valve. ive put in a new fuel pump, i rebuilt the trans when i bout it. no probs with that. it dont matter if im pullin a trailer or if i have my plow on it or jus the truck by itself. but it jus seems like there is never no power. u can hear it shift all gears. when it idles it sets and pulses, when im drivin in town or on the highway it wants to hesitate and act sluggish..two yrs of drivin it still havent figure it out.. it has a recent fuel filter also. and i cant get any troubles or even get the light to flash no matter what stress i out the motor under. to me the exhaust kinda sounds like a loud whistle, kinda thinkin the cat is bad but was told if it dont smell like bad eggs that its not bad. jus tired of messin with it, if anyone can help me out id try bout idea. thanks :confused: :confused: :confused:

[Hicks84s10]

It could be a lot of things. Rich mixture, cat, ect.

[daryl]

With 200 000 miles that could be the problem it could just be a tired motor. But a cat will really effect performance if it is going. Bang on the cat and if it rattles then it's on the way out.

[67Truckin]

Take the catalytic convertor off and either replace it or eliminate it. Your O2 sensor is in front of it so it will not matter. Also make sure the muffler is not plugged or crushed anywhere and flows freely. Try using a can of SeaFoam thru the fuel system. Some engines do not run well when using the gasoline that contains Ethanol. Maybe try a couple tanks of pure name brand gasoline and see if that helps. Does the air intake system flow freely and have a clean filter?
The rotten egg smell people talk about is due to an incorrect fuel mixture which can cause the cat to eventually fail, but it is not indicative of a bad cat only.







Built........not bought! :cool:

[steelhorserider0891]

on the 4.3S there is suppose to be a sticker on the core support. contains the belt diagram, and time specs, and whatever else... mine is gone, does anyone still have theres on the truck. if so could i please get the specs from ya. that another thing that could possibly be that i dont think will throw a code . thanks for the input.

[daryl]

The 4.3 CPI or W from 92-95 was 0 deg timing I am not sure if the TBI is the same though. There should be a sticker there yes.

[67Truckin]

Make sure to unplug the tan with stripe wire at the carpet edge below the glovebox before setting the timing. LMC catalog may have the proper sticker for your truck and maybe you can read it in the catalog. Is it possible your timing gear is worn and has jumped a tooth throwing the timing off?

[steelhorserider0891]

i know bout the plug and everything i jus need the degree its supposed to be set at . my sticker is missing..im not sure the timing for cpi will work as mine is tbi. it may still be the same i dont know.. but if anyone has a 91 4.3 w/tbi thats the sticker i need the info off of.. it should be on the fan shroud or the core support. so if any can help out id apprectiate the help..and thanks for the other replys.

[67Truckin]

I think it is like 0 degrees but, is there a deeper indent than the other ones? Mine timed with whatever the degree was on the deepest indent of the timing tab on the outer edge.

[KTM851]

when i was changin all my fluids this morning i remembered to check that sticker and mine said that is was to be timed at 0 deg and mines an 89 tbi 4.3 so 67truckin u were correct