2001 SL1 Cylinder seems dead.
 

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