Hello, I just got a 91 rodeo sx v6 5spd and I have a small issue. Sometimes when the truck is sitting idle at a red light the tach will jump between 800 and 2000 up and down until I give it some gas, then it will sputter a little but and go.

Once going it accelerates just fine but when I let off the gas enough for the tranny to hold the engine back it will sputter and shake. I have only had it stall once and it usually only does this after ~30 mins. I am also getting these engine codes:

13 Open o2 sensor circuit
44 o2 sensor circuit (Lean exhaust indicated)
45 o2 sensor circuit (Rich exhaust indicated)

I haven''t checked anything out but I''m going to assume by the codes that there is a broken o2 sensor wire which is causing all 3 of the codes but do the symptoms match the suspected problem?

 

I would start with replacing the o2 sensors (dont know how many are on a ''91, replace any before the cat converter). The do go bad after a while. Could also be a vacuum leak, intake manifold gasket bad (not very common on ''91) or something else.

 

Ok thanks, Ill check it out in the morning. I was also told today that it could be a plugged up egr valve. I''ll check both the pcv and egr valves and check for intake leaks tomorrow. I did notice today a wire hanging down around the area of the o2 sensor
[img]smileys/smiley17.gif[/img], Ill post what I find.

 

What did you find?

 

Well not much, the sensor is fine. The distributor cap was badly damaged and the plug wires were very nasty. I replaced the plugs, wires, dist. cap, and rotor and it runs great but it has the light on still with a different code. We have had a lot of snow so I didn''t do it for another week. I am going to start another post about the new code. I guess this one can be closed.