I have recently aquired a 89 jimmy 4x4 with the 4.3 v6. The rig has a new motor and new trans. less than 200 on the motor. It has a msd probillet distributor with blaster coil. It had a holley aftermarket throttle body on it. When I purchaed it, it ran horribly. The holley throttle body was junk. I went to the salvage yard got a factory throttle body and it works great now. My problem is that when the rig shifts into second gear it stumbles for a minute and then recovers. It starts beautifully and runs good. It doesnt stumble under moderate to full acceleration, just when you are easing around (normal driving). Check engine lights are off.....untill you get on the highway at highway speeds. I get an engine code 13 and a code 33. The map is new, the tps is new, the o2 sensor is new, the iac is new. I cant keep the codes from coming back up. The timing is good. I dont know what else to check. I changed plugs and wires the other day. The plugs seemed to me like the engine was running a little lean. I have no way of checking fuel pressure.
Anyone have any suggestions

Also my 4wd all of a sudden has quit working. Transfer case is good, the front hubs just wont lock in. Never worked on one of these before. Let me know what yall think?

 

code 13 - open oxygen sensor circut
code 33 - MAP sensor signal voltage high

the attached pics include a wiring diagram and flow chart for your codes. hope this helps.

 

for some reason I cant open the first diagram you listed. I will check out the one for the map when I get a chance

 

02 sensor wiring diagram and flow chart

http://img693.imageshack.us/img693/3276/graphic.gif

 

Are your hubs manual or auto locking?

 

4x4 No Worky.... Maybe this will help....

They would be vacuum engaged just like all of the other 4wd s-series trucks.

 

hubs are automatic, does anyone make a manual conversion for them?

also thanks for the flow charts, when I get time I will see whats going on with this thing

 

The engagement of the front axle happens inside the passenger side extension tube. You could make it manual with a posi-lock setup (check in the Tech Article DIY section). Due to the hub style that is used on these trucks, there are no manual locking hubs like there are on the solid front axle trucks.