Ok here's the story. My family has a 91 SOHC Max SE. Well we've been battling a missing problem for a couple months now. Changed the plugs, wires, fuel filter. Still have it. It's not constant so I don't think it's something with the fuel pump itself. But it's almost like it's either cutting fuel or spark. I think it's ignition, but don't know what exactly. I also know it could be a dying ECU, hopefully not. Anyone have any ideas on what it could be what I might need to check. Thanks alot.

 

missing as in you can "hear" it missing or the engine is DEFINITELY missing and skipping a cylinder, and you have verified this by removing each plug wire one at a time till finding the culprit(dont think so..)? anyway, mine sounded like it was missing a cylinder or sumpth when the exhaust manifold studs broke. might be that.

 

Well it's actually a power loss miss. You can hear and feel it when it happens. Sometimes it's not there and then it pops up and barely runs. In facted sometimes it even dies. We've had injector problems before with this car. Replaced them and it ran like a champ. but this is a different feeling then that, so I don't think it is an injector problem. But it could be. Hmm, I really hate hunting for problems.

 

hmm...haven't really had much probs with my car in that manner.
check the distributor cap and rotor and if they havent been replaced, try that.....fuel lines (might be pinched somewhere), fuel filter (filter might be clogged).....that's just out of my a$$ considering I dont know too much about diagnosing problems, but they're other things you can check if you havent. Once again, troubleshoot the plugs and wires by pulling them one at a time while the car is running and listen to the engine as you do that. Thats about all i can thing of..maybe some of the other guys have ideas

 

Is your Check Engine Light on?
If so, you might want to get into your ECU and check the error codes. Codes can be found from a Chilton's or something.
Online Chilton

Check you timing?
seeing that you've changed alot of the ignition components, you should try checking the timing. Like the above says, you should also look into your Distrubutor system.

Combustion pressure?
Maybe you have an inner leak somewhere(knock on wood) , or maybe your combustion may have been altered somehow to be too high or too low.

Fuel Pump
Even though your problems are not constant you should make sure your pump is constantly providing enough pressure in your lines. These specs can be found in Chilton's or something.

Fuel Injectors
I'm not trying to question your knowledge or anything, but if you didn't change the fuel injectors yourself, most likely the shop that did it for you used aftermarket or remanufactured injectors. Test each injector's resistance. Optimum/Maximum resistance should is about 14ohms I think, and should not be tooooo far off from this. This spec is somewhere in the Chilton's physical text, not online.

Good luck... I know searching is tiring, but if you look again, gold miners had to search too!

 

My car did that right after i got something fixed, ran extremely rough and would cut off if i put it in reverse. Turned out 2 of the spark plugs werent firing so i was running on 4 cyl lol. but the guy just switched the wires around and it started working again, works fine since.

 

hehe, yeah if the spark is firing out sequence, those cylinders will never run.

 

You should also check your MAF sensor. I know I'm sounding like a broken record (see other posts) but I'm just trying to save others from the year of hell I went through trying to solve this problem.

 

Well it turns out my distributor cap had 2 cracks in it. Put a new cap on and it runs much better, no problems. I'm changing out the rotor bug tomorrow just to be safe. And I will check the MAF. It was a Cattman CAI on it, but that might have fouled the MAF sensor. Thanks again for the help.