1995 Cutlass Convertible miss

[Jay]

Hey guys I have a 1995 cutlass convertible with a 3.4 dohc that has developed a problem I can't figure out .The car has 97,000kms on it and after starting it when the car sat for 2 months It ran rough like it was missing you could hear the miss in the exhaust like a bad cylinder.It eventually smoothed out and ran normal.Ran good for a couple of days then started again.So we thought there was a vacuum leak at the air plenum,replaced the gaskets,started it up same thing!So we checked for spark,was all good then we noticed if we pulled the plug wire off the back cylinder it made no differance with how it ran.Did a compresion test came back at 170 pounds.Now we think it could be a bad injector on that cylinder.To bad the injectors are under the plenum which we just had off!Is there anyway of checking the injector?Is this a common thing on the 3.4 or coould it be anything else thanks for your help.

[eekitt]

Bad intake gasket

[93Oldsdroptop]

Bad intake gasket

Agreed. Very common 3.4 problem. These engines stock LIM gaskets are shit. Get a Fel Pro set and it will be much better. To confirm this diagnosis, spray some Clean_R_Carb around the ports of the LIM when it's cold. If your idle changes, that's your confirmation.

Good Luck!!