Service Engine Light code-Multiple Missfire

[Pete Lech]

Three times recently, I started the car after it had been parked on a slight grade and it began missing badly, but cleared itself in a 100 yards or so. Then the Service Engine Soon light came on. The scanner code was Multiple Cylinder Missfire. I cleared the code, and it seems to be OK now - I scanned for new codes, but there were none.

Is this a leaky injector? Do I have to wait for another major episode, or is this a fluke?

110K miles, new plugs, etc. at 100K. I haven't run any Injector cleaner thru for a while.

[GTP Dad]

It is very possible that this is just a one time event. If it happens constantly then you may want to try to diagnose it at that time but otherwise don't worry too much about it. If you changed the plugs you may want to put on new wires too especially if the ones on the vehicle are the originals. This will help the engine to run better due to increased spark voltage.

[kmohr3]

I wonder if you have a fuel preesure regulator leaking down a little, causing you a few seconds to build up fuel pressure in the fuel rail? What engine 3.8 or 3.5?

[Pete Lech]

It is a 3.5.

I put a bottle of Chevron ProGuard Injector cleaner with 10 gallons of gas last night and will watch my fuel mileage, which has not changed since I bought the car in 2000 with 28K miles.

Is the service life of the ignition wires in the 100K range? Met a guy with a 3.5 Aurora who had a wire fail at 120K. What about the coils on each cylinder?

[GTP Dad]

The life span of wires varies by vehicle. There is no set amount of miles that a set of wires will last. I have had wires last less than 1000 miles and more than 100K miles. If you are having performance issues there is a good possibility that the plugs and wires are bad. Since you changed the plugs then you I would change wires too.

It is possible that the fuel pressure regulator is starting to go bad and is leaking down as kmohr3 said but that may be hard to duplicate unless it happens again.