after the truck warms up i have a slight hesitation around 45+ mph. it occurs when the truck receives part throttle. if i give it a little gas the rpms dont go up and i have to hit it about 1/3 to 1/2 way for the truck to really move. is this normal? also it's more like 35+ mph when the heat/ac is on. thanks in advanced.

 

You need to post some more info:
What year truck?
What mods?
When was the last time the plugs or fuel filter were replaced?
Robert

 

stock 2000. i just bought it a little more than a week ago.

 

I'd grab a rachet and make sure ALL the plugs are snug.

and go from there

 

I would also check the fuel filter, it could be clogged

Did you buy it from a dealer or private sale? Can you take a picture of the engine? Maybee the previous owner put a 90 MM mass air meter on it, and had a chip for it. The chip may have been removed, sometimes dealers remove that kind of stuff.

I don't know whats going on just making a wild guess.

 

no everything is stock on the truck. i forgot to mention. when you first start it up it runs fine. once it warms up it starts it. open/closed loop issue.

 

its not converter lock up is it? or is it worse than that

 

I would check my plugs first if I were you. The hesitation could be from a burned plug.


Fuel would be my next step.

Suavy

 

Start fresh with a preventive maintenace schedule. Change plugs, fuel filter, oil...etc. Then you have a baseline to start with.

You have no prior knowledge of how that truck was maintained do you?

 

no i have no idea how the truck was before me. it's not TOO big a deal, i can still drive it, but it's something i'd like to have fixed. it's 45+ and 35+ with ac/heat on. if you give the throttle like 2" the rpms dont really go up, you have to hit it more than half way down for it to really move. when you first turn it on it's fine, it's just once it warms up. i think it's probably a plug.

 

what about an o2 sensor? bc of the open loop/closed loop problem?