My girlfriends 97 olds cutlass with a 3.1 has been having issues for over 6 months now. It was throwing a EGR code as well as a cam position sensor code, I replaced the cam pos sensor, and made a EGR block off plate, the problem didn't change at all. Just today I put a used EGR on it, and cleared the code, but still the same issue.

The car will sometimes just randomly cut out while accelerating, in any throttle position. If it cuts out when I'm starting from a stop, and I let off the accelerator, sometimes the idle will surge to around 1,600rpm and make the car pull forward...
Sometimes it randomly dies at stop lights. Sometimes when you start it up, it acts like its missing really bad, and shakes the engine really bad and barely runs and barely revs..

But then other times, it runs strong, runs perfect to redline, at any throttle position. Pulls hard gettng onto the highways... Othertimes like I said, it cuts out, repeatedly.. once your up to speed, generally it can hold speed, like a tiny bit of throtlte is fine, just not a lot..

I've changed out the EGR now to a known good used one from another vehicle, I put new plugs/wires/fuelfilter/air filter. I just picked up a throttle position sensor today I'm going to swap after work and see if that helps. Other then that I'm lost.

I really want this car fixed, but its not throwing any codes anymore since I fixed the two codes it was throwing... It has 165k miles on it, and hasn't had any other issues in the last 2 years.

 

Check all of the vacuum hoses and connections. Get a can of carb cleaner and spray it at the hoses, throttle body gasket, intake where it meets the heads, anywhere there could be a vacuum leak. If that pans out I'm stumped, but this sure sound like a vacuum leak to me.

 

I forgot to add I tried that, 3 different times.

I've been working late and haven't had a chance to put this TPS on it yet, but if that does fix my problem I'll post up letting everyone know. I'm stumped as to what it could be =\

 

Sounds very similar to my 3.1, I replaced the TPS with no luck. Be very careful with the two mounting screws, it's easy to strip the threads in the holes if you are not lined up perfect. I have tried to repair my 3.1 for over a year and it won't go two miles. Took it to a professional and he wanted $1000 to replace tank and pump, did it myself but still ran bad. I replaced the throttle position sensor, plugs, wires, fuel filter, map sensor and got all the codes cleared so then I replaced the ECM too and still no better. When I gave the guy at the parts store the numbers off the old ECM he couldn't find it on his chart so I took a chance and bought what he had for the 1992 3.1 but I'm wondering why he couldn't verify the old number, maybe I screwed up but I am in desperation mode with it by now and with the pros wanting $1000 for a gas tank replacement taking it back to them is not really an option. It has only 100,000 on it so I hate to give up on it. The old ones were simple compared to this. I'm still on it, if I get lucky I'll let you know.

 

I had a problem with the check engine light. Took it to a mechanic and he told me he thought the ports might be carboned up. Said he didn't have time to do it and told me how I might fix it. (you don't find too many of those guys around). Any I took the EGR valve off and the big hose from the air cleaner off. I took what looks like a big pipe cleaner and shoved it through the port between the EGR valve and and the air port going into the manifold. A first it barely went through. I put carburator cleaner in and kept poking it through until it moved freely. There was so much carbon build up in there I couldn't believe it. The hole was probably down to a 1/8 inch when I am guessing it should be about a 1/2 in diamater. Anyway I put it all together again and no more check engine light and perhaps a little more power and better gas mileage. You might try that before you spend a lot more money. The proceedure should take about 1 1/2 hours or so. Good luck.

 

Well now I've replaced a bunch of stuff, still no fix. I got the TPS replaced, the 'mass airflow sensor', the idle control valve above the TPS, some little box thing that was bolted to hte intake manifold and had a vacuum line to it, still doing it.

I also tried using carb cleaner and spraying EVERYWHERE to see if there was a vacuum leak, couldn't find anything.

I work as a mechanic and scrapper, so we get malibu's and cutlasses in all the time with these 3.1 motors. If I can figure out what part to pull off to try and swap, I can do it for free. Hell we just had a malibu in last week, and I snagged all kinds of crap off it for backup parts, a rebuilt alt it had, ac pump, power steering pump, coils + new wires that were on them.. All free

 

Sorry to hear you haven't cured it yet Towlieee, I plan to try the carb spray Monday or Tuesday, as soon as I can get past some of my other projects. I've got the engine tipped forward and I've been running it that way just so I can see the backside for problems, doesn't seem to bother it to run that way, maybe I'm screwing up but hey, I am desperate to get it running for my wife. I told her no more computer brain cars, I'm putting her in a 75-85 4wd Chevy pickup, dependable, bulletproof and easy to work on. Let us know if you come up with anything, thanks for posting, Good Luck!

 

Yeah sorry you can't cure the problem.I was thinking if it was the intake manifold gasket it would leak some oil. These 3.1s are know for that problem. Just for laughs run a compression check on the engine. Good luck.

 

Hey Towlieee, I worked on my 3.1 today and I'm thinking that the fuel pump is at least part of the problem. I've got an access hole cut behind the rear seat so I don't have to drop the tank to get at the pump and I can hear the pump real clear when I turn the key on. The engine would only run for thirty seconds today and if I turned the key right after it died I wouldn't hear the pump and the engine would struggle to re-start and run very rough. If I waited about twenty seconds to turn the key I would hear the pump and the engine would start with no problem and run steady but only for about thirty seconds. It did this consistantly over and over. I put a new fuel pump on last fall but the car never did run good enough to put any miles on it and I'm thinking that I got a bad one. I don't think a bad fuel pump would show on the codes, the only thing I see in the manual is #54 low voltage-fuel pump circuit. I'm thinking it is more of a mechanical failure and can't hold the pressure rather than an electrical failure. If you want to cut an access hole rather than drop the tank just pull both rear seats down and peel back the carpet from the trunk. Right behind the back of the seats you'll see a pattern of five grooves or depressions stamped into the metal panel, the center groove runs right over the fuel pump assembly on the top of the gas tank. I took a good sharp chisel and bopped a good line about three or four inches to either side of that center groove and then joined them in the middle like a letter "H", peeled them up and went to work. When you're done you can press it back down or you could make a cover and secure it with a few sheet metal screws. It sure beats dropping the tank if you don't have to. I used a whole can of carb spray today with no result. Let us know how you do. Later, Phil.

 

Hey Towlieee, if you are still out there trying to fix that 3.1, I got a clue from a wise man and I'm gonna try it asap, like in 48 hours and I'll let you know if it works..hang in there and don't junk it yet..Phil.