Misfire!
 

The SES light came on 3 days ago. Looked up the code and it was cylinder 5 misfire. The vehicle emits a "put put put" sound ONLY at idle, but runs strong at freeway speeds. The code disappeared twice today, but returned shortly after. I took it in to get a diagnostic and this is what they said:

"Customer request cylinder misfire. Diagnosed cylinder misfire. Retrieve DTC's from computer. Code P0305 present,cylinder 5 misfire detected. Code P0316 present, detection misfire on start up. Checked fuel pressure. Fuel pressure in specification at 51 P.S.I. Listened to fuel injectors for noise patterns. Injectors sound good. Spark plugs and coils are brand new and in working condition. Performed vacuum test. Found that at 18 P.S.I in drive there's a fluctuation. Problem happens at low RPM's. Issue at hand is a mechanical problem. Possible burnt or sticking valve. Recommend trying fuel injection service and chemical/additives first. Use Top Tier gasoline only with additives"


Current mods on the car: JLT RAI, UD pulleys, and chambered design mufflers. The vehicle runs on 5w-20 Mobil 1 synthetic oil with a Mobil 1 oil filter. Car has 80k miles, it's an automatic that is used 2 times a week for 74 miles a day.

My question is what can be done to stop it from sticking? Or worst case scenario, what am i looking at to replace a burnt valve?


Thanks and please help. I would appreciate it.

Re: Misfire!
 

Anybody??

Re: Misfire!
 

Pull the coil cover and look for water. Reseal coil cover end with RTV.


LS:claus:

Re: Misfire!
 

Been there, done that.:eyes:

Re: Misfire!
 

Did not do a compression test on # 5 ? Should have, if thats ok then have them clean the injectors .Then put some Marvel Mystery oil in the gas and oil as per instructions. It is an valvetrain /fuel system lube and works good for sticking valves.:smokin:

Re: Misfire!
 

I guess not. That never crossed my mind. Darn!! So far today I've tried the lucas fuel injector cleaner and some other brand by EZLUBE who also did the liquid by sucking it through a line. I think I might try seafoam tomorrow in the after noon. I'll also try what you just recommended. BTW is there a cheaper alternative than buying new heads? I was told a port and polish job MIGHT help. Any insight on this theory or theirs?

Re: Misfire!
 

Any other suggestions? I'm getting desperate...lol

Re: Misfire!
 

Update! I pulled my spark plugs and they look like this! Is that oil? I have a feeling this isn't normal.

FYI I've never used any octane booster, but I am guilty of using fuel injector cleaners like lucas, MM oil (one tank) and other additives to "clean up" fuel lines. I use Mobil 1 or K&N oil filter with Castrol synthetic or Mobil 1 Synthetic 5w-20 with an occassional Lucas oil stabilizer. I also have a JLT RAI.

Re: Misfire!
 

I wish all the plugs I changed looked that good. Nice clean burn. The ceramics don't look brown or discolored. Those look like they are fine. There is a contingent of people out there that do not like the four electrode Bosch plugs. They say it causes issues. Maybe you can try some plain jane Autolites or the single electrode Bosch and see if that helps.
If you had bad blowby those plugs would be much, much worse.
Have you tried switching the coil pack for Cyl 5 to another cylinder to see if the misfire follows? That is a BMW trick I learned since those things eat coil packs. Not even sure if you can do that on one of these motors (I am still learning my Mach) but that is the fastest, easiest and by far the cheapest diagnostic you can do.

Re: Misfire!
 

"Spark plugs and coils are brand new and in working con." How long ago did you change these in relation to the Misfire?

Re: Misfire!
 

Pardon me for not being thorough in my description. These were the "older" plugs which I replaced with Motorcraft Iridiums. Sorry for the confusion

Re: Misfire!
 

Since this is all new stuff, I'd put a dollar on the fact that you got a crappy coil in the batch. Swap it with the one next to it and see if the code moves with it.

Re: Misfire!
 

The coils are new and in working condition. I took another members advice and added Marvel Mystery oil into my gas tank to see if that'll loosen up the "sticking valve"(I sure hope that's the problem). I say a couple more gas tanks of this treatment and we'll have to wait and see. I'm also planning on using seafoam to get rid of carbon build-up.

Re: Misfire!
 

UPDATE!


The vehicles SES light disappears after a full tank of gas w/ MM Oil. From time to time the vehicle hesitates to start and feels as if it's going to die so I usually push the gas pedal when I hear it cranking and vroom she starts fine. The "put put" sound is only present in a quarter tank of gas. I'll be heading to another diagnostic. I have a feeling this is a big fix fellas.

Re: Misfire!
 

could be a long shot, but ive had a bad spark plug that was new. it misfired and stumped the crap out of me. plugs have a 1 year warrenty most of the time, pull them all out and put all new ones in. wont take that long and its free.