My 2001 saturn seems to be dead on one cylinder. Runs rough at idle but on highway not realy noticible. RPM at idle varies by 200rpm.
Overveiw:
New wires plugs and plugs. Have done compression check and results 195,200,200,200. Lots of spark on sparkplug end of wire with disconnected from plug. OB2 code say missing on #4cylinder.
Not sure how cylinders are numbered but beleived from front to back of engine. When I remove, beleived to be #1 cylinder sparkplug wire (Front cylinder) no difference in engine running. When any other removed, engine stalls. Coil packs swaped no change.

Any Ideas? Was thinking of swapping injectors next.

 

I think you may have an intake manifold leak. Spray some carb cleaner or starter fluid around the #1 cyl., where the manifold bolts to the head and see if the idle improves.Injector problems are extremely rare on these cars, intake gasket problems are not.

 

I never conciddered an intake leak do to it having injectors. So to speak in the old days of carbs this would have been the third thing I would have concidered. Can you breifly give me an idea how an intake leake would cause this? (Just want to understand.) I could definatly see this if the injector were in the intake and not the head. Have not looked closely behind the engine from the top. I will check this this weekend.

Calvin

 

I have just looked at my repair manual and on the DOHC engines the injectors are in the intake. Did not concider this intake problem. I am pissed at myself that I did not look in this direction.

Calvin

 

I thought you said you had a SL1.

 

Yes SL1. Thought injectors would be approx in same place.

 

Problem solved with intake gasket!
Thanks for the help.

Calvin