Ok, so after I changed out the coil packs and spark plugs in hopes of resolving the misfire issue and to no avail...I took it in to the dealer to have them run some diagnostics on it. Error codes are attached.

They did a vacuum test/smoke test, checked the MAF and checked out something with the throttle. All of those were good. I also had them check out a small oil leak that's been going on since around the same time that the misfire issue came out. They said the oil leak is coming from the bottom back side of the oil filter housing. They also said that there is a small transmission leak and it needs resealed. They are telling me the engine has to be dropped to get to the oil leak, so they quoted me around $4K for the repairs. They still have no idea about the misfires.

Not sure what to do at this point. I went ahead and picked the car up. Considering dropping the engine myself this summer, but that will be quite the project as I've never done that before and I don't have all the tools I'll need. Also considering getting rid of the car after reading many others' horror stories about the misfires and huge repair costs.

Any thoughts or advice?

V/r,
Travis

 

don't need to drop the engine to fix an oil leak at the filter, could be it's just oil spilled from an oil filter change.

As for the misfire, did you use the updated 997 coils and what plugs did you install? How did the old ones look (plugs and coils). Also were the codes cleared after you did the plugs/coils? Those could be old codes, you should have them cleared and rescan next CEL.

Dealer mechanics must make a killing fixing all of the problems with a $4k r&r bill that isn't needed...

 

Yeah, I changed the coils/plugs with the Bosch Ignition Service Kit from ECS. http://www.ecstuning.com/Search/9976...KT4/ES2550866/

They were saying that the oil leak was coming from a metal housing near the oil filter that they can't get to. I haven't had time to dig around in there myself to look at it. No CEL on right now. It had been on for over a month constantly, but went off like two days before I took it into the dealer.

 

so did the misfires etc start after you changed the plugs and coils? If not , did you do anything else just before the issues to the car?

 

Likely the leak is from the oil pressure sender #45 in the below picture or the line #15 connecting it

Misfire could be bad fuel, when does it happen? All of the time under boost or part of the time. Looks like some of those other codes could be the problem as well.

No CEL but still having misfires?

 

No, the misfires were there before I changed the coils/plugs. That's why I changed those. I hadn't done anything else to the car.

The dealer did ask me if the car was tuned/re-flashed though. I have no idea. Is there a way to tell?

 

Thanks for the diagram! Misfire happens under heavy boost pressure, usually above 4K rpm's. It's almost like it's hitting a rev limiter. I was going around 70 on the hwy, went WOT and the car would literally not go any faster or make any more power. However, if I ease into it with the throttle, it doesn't really have a problem with getting up to higher speeds around 90 or so. I haven't wanted to test it above 100 in fear of damaging something.

 

I see,
did you buy the car like this? or did it happen sometime after?

bad gas? old? is the fuel pump working? if your getting odd misfires its bad gas or low fuel, pump may be going out... do you hear a whining noise when you open your truck?

 

Gas doesn't seem to make a difference, whether it's 91 or 93. Car was fine for about a couple months after I bought it. Lots of power and boost; no misfires.

The dealer did also inspect the fuel pump and it checked out well. Forgot to mention that earlier. Not sure about the whining noise. I'll listen for it tonight.

 

How much boost does your display show?

I had some bad coils and worn out plugs, car still pulled hard but it would buck now and then through the rev range. Usually it's worse around peak torque so ~4k sounds about right depending on turbos.

I'd recheck the codes in the computer, the dealer likely cleared the old ones so anything showing now will be relative to the issue.

 

What plugs did you get ?
Are the midfires on one bank only or all over ? How many cylinders misfiring ?

How much boost ?

 

Did you correctly gap the spark plugs? I use NGK Laser Platinum PFR7B and gap to .028.

I think the gap might be the problem...

Good luck.

 

The quote below is what made me suggest the gap in the response above.

 

According to the printout the dealer gave me, it's cyl 5 and 6. I used Bosch FR6 LCD plugs.

Not sure on the boost, I'll pay more attention next time I'm driving it. What's a normal amount for stock?

I believe they were gapped to .025. Maybe I should double check them? How big of a difference would .03 make?

 

get these plugs dont gap them just put them in...
Denso 3245 PK20PR-P8 Double Platinum Spark Plug
Item# DEN3245

on dash it says how much boost ... you should see .7 bar...