Ok, 1993 960, check engine light came on yesterday, I pulled the codes and got 2-3-2 and 2-1-2 which I believe are for a lean idle and o2 sensor. Based on what I've read, I should check the MAF sensor first by cleaning/unplugging it while the car is running. correct? If it runs better with it unplugged then I'm assuming I need a new sensor. As for the o2 sensor code I'm curious, because the sensor is a direct bosch replacement that I put in about a month ago. Do you think the sensor is just giving an incorrect reading due to the fact that the car has a lean idle?? I need some help/ideas asap, because I'm going on a 300 mile trip this weekend!
~thank you everyone~

 

Sorry so long to reply.
The Mass flow or Vaccum leak might set the O2 code.
Check for a vaccum leak as well.

 

I've been gone for the last 4 days....but I cleaned the MAF sensor and checked for vacume leaks and couldn't find any. I reset the codes and didn't get a check engine light till 20 miles later...this time is was just the o2 sensor. I got home and made sure it was in tight and all the connections were good, and then reset the codes. About 150 miles later the CEL came back on, and again it's the o2 sensor. So either there is a vacume leak somewhere that I can't find, or the o2 sensor is faulty (thankfully it has a lifetime replacement warranty)

 

O2 sensor.

 

yes, it is definitely the o2 sensor. Any thoughts on why my new sensor would fail so quickly? Could it have just been a bad one? Or do you think it may be a bigger problem?

 

Could be either.
I have seen many new parts bad out of the box.
If it is pretty new is it still under warranty?

 

yeah, I've only had it for about a month. It has a lifetime warranty though, so I ordered another today. It'll be here in a week. Hopefully the new one will be good.

 

alright, put in the new o2 sensor today and cleared the codes. I was getting the lean idle mixture code and the o2 sensor code....I'm assuming these both relate to each other. Car seems to run really good again, and I'm hoping everything is set for a while. When I pulled out the bad o2 sensor it was really sooty. Does this mean the car was running rich? and could it have damaged anything? Also, would the faulty o2 sensor result in severely decreased gas mileage? Right now I've only gotten about 150 miles out of a little bit more than 1/2 tank, whereas I typically get much closer to 200.

 

Yes that usually meas rich.
Yes it will result in bad gas milage as well.

 

ugh! The new direct replacement o2 sensor is in, and I've driven about 60 miles. It idles perfect now. However, today on my way to work the car was surging a little at speed. When running at roughly 2500 RPM it would surge up about 100-200 Rpms. Now, lo and behold the CEL is on again, and the only code is 2-1-2 (check o2 sensor)......seeing how the sensor is less than 48 hrs old, where do you suggest i look next?? This is starting to get really frustrating.

 

Vaccum leaks.
That would be my next move.

 

ok. Anything specific I should check? I used to own an 85 toyota landcruiser, and it had over 35 feet of vacume lines, so I've gotten fairly good at finding leaks, providing I know the general area that they may be in.

 

Check all hoses by the Vaccum tree.
Also check for leaks at the injectors.

 

ok, all hoses and everything along the top of the engine is tight. I disconnected the battery for about 2 hrs yesterday as well, so we'll see if that does anything. So far I've logged about 12-15 miles of city driving and everything seems good. I guess I'll know soonif it's going to throw the CEL at me again...[sm=owned.gif]

 

damnit! It threw the CEL after 2 days and roughly 15 miles of driving. Engine still fluctuates about 200 RPMs when I'm between 2500 and 3000 rpm. However, it only happens when I'm going less than 60. Kind of weird. Also today I noticed it was idling a little lower than normal, but after some stop and go, the rpm needle was back up to its regular spot. I have no lack of power, the car isn't missing a beat, and it's running smooth. When I got home I tore into it and checked all the vacuum lines, checked and cleaned any necissary electrical connections, took out and inspected the o2 sensor and checked all its wiring, checked all coils and injectors, checked all grounds, cleaned the throttle body and flame trap, and made sure that nothing was binding in the throttle cable.....what else could it be?? Tomorrow I'll be making my 30 mile round trip commute to work so I suppose we'll see what happens then. I'm broke, and trying to avoid a mechanic if at all possible, and this is starting to become a bit of a PITA.

 

Have you tried spraying carb cleaner around the intake while it is running?
You may also want to do a compression test.

 

I know compression is good. I'll try spraying some carb cleaner tomorrow and see what happens. Still can't understand how the only code I'm getting is for the o2 sensor. It runs great, and I'm getting about 22mpg mixed driving.....

 

Got home today and sprayed carb cleaner all around the throttle body, and anything intake or vacuume related. I got absolutely no change in engine speed at all. I cleared the codes, checked all the vacuume lines again, and then with the car in park revved it up to 2600rpm, the engine stayed steady with no surging at all. I started and restarted the car several times, to see if it would throw a code, and got nothing. This is so weird....but I've gotten about 300 miles out of 3/4 tank, so I'm not complaining that much.

 

update: I called a mechanic yesterday and he told me that since it is an OBD1 vehicle the o2 sensor code I'm getting could be related to something like the MAF sensor, since it supposedly works in conjunction with the o2 sensor. Does this sound correct? I've pulled the MAF plug and the engine ran really rough, but that was only at idle. Is it possible for the MAF to only work intermittently at higher speeds? Hence the surge I get around 45-50 MPH and 2600 RPM's?

 

well, I drove to colorado this weekend ~650 miles. On the way there I was getting only about 250 miles out of a tank...absolutely terrible. Took it into a volvo specialist and he found that one of the wires going from the plug to the engine was broken, and thus caused the o2 sensor to not function. $225.00 later he replaced the plug and wiring, and put in a new sensor. The car runs good as new now....I drove across the entire state of Wyoming and part of Montana on one tank of gas, so my great MPG is back. Finally the 2 month ordeal is over!!