[orkinmann]

91' 1.9L auto 216,000. I've come across this problem 3 times now. if I'm driving on the highway for more than one or two hours, the check engin light will come on (doing between 70-80 mph) and it will go off after a short period when i see that, get scared and drop it 5-10 mph.

My question is this... It's not banking the code, and I have no clue as to how to check this problem otherwise... I spent an entire day trying to pull codes and I got all clear on all three fronts each and every time (Unless it wasn't properly warmed up then i got a i think it's a 22... which simply means that it's not warm enough to give an accurate reading)
How do I get this ellusive code to reveal itself.... do I have to drop to neutral, shut it off with the light still on, and pull to the side of the highway to decipher the code?

 

[zzyzzx]

How old is the O2 sensor?

 

[ethangsmith]

When the check engine light comes on, does the car do anything odd (lose power, ping, stutter, surge)? I would agree that it may be the O2 sensor, but it would be best to see what is going on.

 

[EscorGo]

I thought codes are stored in the memory.
Maybe there's something wrong with the check engine light itself. What symptoms are you seeing?

 

[ethangsmith]

Being that the car is EEC-IV and not OBDII, it is not capable of the self-diagnostics that more modern cars are. KOER only tests inputs/outputs with the engine running in its current state. KOEO tests the sensors as the computer does its prove out. It does have a Continuous Memory, but it is only capable of storing certain codes.

 

[orkinmann]

o2 sensor was replace maybe 4500 miles ago... I get no symptoms... because of this i'm worried and i'm not t the same time

 

[dave8338]

I think a compression check may be in order... :?

 

[orkinmann]

I know that the compression check that the computer will do on it self I(I think you have to WOT after all the EEC tests are done) came back with fine results and I could tell no difference between cylinders. (The computer will systematicaly: shut down cyl. 1, run all, shut down cyl. 2, run all, shut down cyl. 3, run all shut down cyl 4, run all, then I think it balances them out based on preformance.... I think...) I could tell no difference between any of the cylinders being shut down. 1 felt like 4 like 3 like 2. and of course all running felt much better than only 3 running at a time. Do you still think I need to do a scary comp. test?

 

[FordMan59]

It could be the ECU itself. I had one go out on my '88 Pony one time and I couldn't get any codes from it.

 

[Setnev]

Well, I too have a similar issue with my 95. I will be driving down the AZSR-51 through the Phoenix Nature Preserve (speed limit 65, very long but steady right curve) and if my fuel is around or less than 1/4 then the car will sputter like its running out of gas and from time to time the Check Engine light will flash till it regains power. I figure it is from the fuel level being low and the fuel being pushed to the side of the tank by centrifugal force and starving the pump.

 

[Blueescortproject]

i've been having the same problem with a 94 cutlass that iv'e been borrowing; light comes on after wrmed up and no codes shown when tested. luckily there isn't any performance issue when it does come on, i'm just gonna pull the bulb.