hello i am new to this forum
i need some help with a 1991 3.1 that has a misfire since there is no obd2 port on a 1991 cant just plug a scanner into it
the car is a 91 cutlass supreme convertible with 43000 miles on it
we took it to the dealer thinking they would have a mechanic that might be old enough and know something about these cars
well they checked the crank sensor and replaced the plugs and wires and check all the coil packs and the module behind the coils and could not figure out what it is
i need someone with some oldmobile or gm 3.1 experence in these cars that had a ecm but no port to scan for problems
well ill be waiting for replys thanks in advance

It does however have an OBD1 port.Of wich you can gain codes with a paperclip.Yes a paperclip.Heres how complete with instruction and code elaborations
http://www.extreme-check-engine-ligh...%20Decoder.htm

sometimes you get a good dealer tech but most times not lately. everyone ive talked to, if its not in there troubleshooting table they are lost. check the coils terminals and ICM terminals sometimes they build up corrosion. if its not that have to get into fuel side, pressure, injector, etc.

Dakota is correct about how to check for codes on your car. Follow the instructions in the link he provided. If you have checked the plugs, wires, coils and ICM (module behind the coils) your problem could be fuel related. If the fuel filter has not been replaced lately, replace it. Have your mechanic check fuel pressure are the fuel rail. If it is low you probably need a new fuel pump. If the fuel pressure is good, you may have a bad injector. You need to know which cylinder is misfiring. Get the trouble codes and post them for us to review with you.

thanks for the replys so far i am relaying these to my son that owns the car who is stationed at camp lejune in nc he has no mechanical skills at all so walking him thru this on the phone is painful please keep sending suggestions and i will post results when i get them

Reading the codes (use the paper clip method) certainly helps to narrow down the list of suspects.

ok this we know for sure so far it has a code 23 (intake air temp sensor out of range, low)

could this cause a miss ?

and will disconecting the battery erase the codes?

To clear the codes, turn the ignition switch off, disconnect the negative battery cable for at least ten seconds, then reconnect it.

I've never heard of an IAT sensor causing a misfire..did the dealer do a compression test or check the injectors?

i wasnt there he took it to the gm dealer in nc
i can call and ask them tomorrow if they did though
compression test or leak down test?
i can see there being a bad injector o ring for the little amout the car has been driven
remember this car only has 43 thousand miles on it and yes they are documented miles
but the original owner only drove it on the weekends to the store a mile up the road and back once a week so i dont understand how there could be a low compression problem but i will find out