Chrysler Repair: engine missing on one cylinder: 2.5L V-6, distributer cap, chrysler cirrus

Question
QUESTION: number 4 cylinder missing. have replaced plugs, wires, distributer cap and rotor..what else could it be? if injector what can i do for that

ANSWER: Hi Ron,
What is the year,make, engine please.
Roland

---------- FOLLOW-UP ----------

QUESTION: 1998 chrysler cirrus 6 cylinder 2.5

ANSWER: Hi Ron,
It either has to be a mechanical issue (valve/cylinder-piston) with that cylinder or a fuel injector issue with that cylinder.
You could do a compression test on it and compare that to the #2 and #6 cylinder readings. Do it with the engine warmed up.
On the injector, you could verify that the wire that 'drives' that injector is patent to the pcm: light blue/brown wire to pin 16 of the front plug, using an ohmmeter or continuity testor. Also verify that the dark green/orange wire at the injector plug shows 12v while the engine is running. When you take the plugs out to test the compression see if there is a difference in the appearance of the three plugs (more wet or more dry?) which would perhaps be indicative of a injector running-on or not running at all.
If you conclude it is the injector then you have to remove the fuel rail and disconnect the injector. I can send you a few pages from the manual that show how to do that.
That is about all I can offer.
Roland

---------- FOLLOW-UP ----------

QUESTION: thank u for your answers..one final question..and yes would like those pages please..have had vehicle put on code reader twice..first time said number 3 and number 6 cylinder..this time said number 4 cylinder. could that be something more like a lean fuel condition?

Answer
Hi Ron,
That is good to know as it takes the focus off of a specific cylinder as you suggest.
The first thing I would do is check the mechanical function of the egr valve which is located along a pipe that runs from the left exhaust manifold (on the side of the engine facing the front of the car) to the intake manifold area (where the incoming air in the large rubber tube enters the throttle). That valve is metal and has a round fitting with a vacuum hose attached, mounted on the top of the valve, and the round part is attached to the main body of the valve by a sort of saddle.  Inside the open saddle you will see a metal rod (with a slot) that connects the round top fitting to to the valve body. That rod is a stem on the valve and it is supposed to go in and out in response to the engine vacuum which varies with RPM and throttle opening (gas pedal position). Take a spray can of WD-40 or other penetrating lubricant and spray the stem where it enters the valve body and then use a regular screwdriver blade tip inserted in the slot to lever the valve in and out to try and free up its motion. Also check all the rubber vacuum hoses associated with the valve and a nearby vacuum solenoid valve. If the valve seems to open (against the action of a spring) and close firmly by the spring action when using the screwdriver blade to facilitate the motion then that should be a well-working egr valve. It is is sticking slightly ajar now, that would indeed lean out the mixture and cause missing on one or several cylinders.
Once it is idling, check that the valve stem moves when you rev the engine from idle to 2500 rpm and back to idle.
Other than that valve, perhaps checking the fuel prssure going in the rail would be worthwhile. It should be about 49 psi. You would have to get a gauge, and an gauge adapter hose to plug in after disconnecting the fuel line, as the set-up from the factory doesn't have a test port for fuel pressure. But maybe the egr will prove to be the issue.
Roland
PS Please 'rate' my answer using the 'thank/rate' tab, and where you see the question about 'volunteer of the month' consider giving a 'yes' answer if this has proven to be helpful.
Thanks