My 91 Max SE started acting up about 2 months ago. All of a sudden, one day, it started getting real sluggish and jerky during acceleration (felt like it was running on 5 cylinders). It's a 5 speed and I have to rev it up to about 3 grand just to take off from red lights. I did a full tune up (plugs, wires, cap, rotor button, fuel filter, air filter, pcv valve) with no luck in fixing the problem. I then changed the distributer and ignition module. Once again... no luck fixing the problem. 2 days later.... everything cleared up and ran fine. Stayed that way for a week and a half and then started acting up again. So then I did the self diagnostics on the ECU and it told me that it was the oxygen sensor. I changed it and no luck fixing the problem. Once again, cleared up for a week or two and then when back to the same problem. I've also put on a new EGR valve, checked for any vacuum leaks, added fuel injection cleaner, and what the hell.... even washed, waxxed, and detailed the whole car. What else can I try. I am getting desperate. Thank you for the help and sorry if you guys have already answered this.

BTW I can still do the self diagnostics on the ECU and it still tells me that the Oxygen sensor is bad (code 33).

 

if the ECU still thinks the o2 is bad then :
A. o2 is defective
b. Wiring is bad.
c. ecu is bad.

My money is on b

 

Im pretty sure that washing waxing and detailing won't fix the problem....

Sorry about the sarcasm...

Brian

 

K... exchanged my o2 senser, checked the wiring with a voltmeter, and swapped out my computer with another 91 SE with Manual tranny... still says the same thing... I'm lost.

 

maybe a shortin the o2 sensor wire somewhere along the wire that maybe is reading fine now, but if you played with it it would read diffrently. what about if u do a complete reset. someone said that if u diconnect the battery and pump the brakes like 30 times its a complete reset, i think thats what it was.? cant think of anything else right now

 

Do any of you guys know if a leaky intake manifold could cause the O2 sensor to read bad to the computer? I have replaced all the vacumm lines and it still sounds like I have a vacumm leak under the intake manifold. I have my wife going to pick up some carb cleaner to spray around it to check for sure. But, if any of you guys know if the problem of the O2 sensor could be because of this......