I've got sort of a mystery problem right now that maybe you wise Jaguar sages can help me with. I currently have a recurring CEL the dealership seems to be having alot of problems diagnosing.

First I had misfiring in cylinders 1,3, and 5. They checked the coils and plugs and replaced. The next day it popped up with an engine bay 2 too lean code (P0174 I think). This code existed before the coil replacement but they turned it off to see if it would recur. They checked several times for vacuum leaks and claim there are none. they then did a fuel induction/injection service. Next day, CEL back on with the same code. They've had it since yesterday and don't seem any closer.

When I start it up cold after they have turned off the CEL, I get a restricted performance blinking CEL, and then the light remains on.

The car also no longer accelerates well at all. When mashing on the gas to get out of a parking lot quickly or make a left turn, for example, there is no power at all for about 2 secs and then the RPMS start to climb quickly with very low associated acceleration. Also, if car isin 3rd or so (driving down the road) and I step on it a little harder than, say, medium throttle, i get really patchy, uneven acceleration.

The dealership claims they can't recreate the performance issues either, which I'm having trouble believing. The car used to squeal tires if I hit the gas to hard. I'm not one for squealing tires but I had to make a note to not floor it so hard. Now, I have to wait for traffic to be completely clear to pull out.

any guidance anyone may have would be fantastic.

 

Take a read on a thread I started.

https://www.jaguarforums.com/forum/s...d-going-44855/

Mine, too, started with misfires on one bank.

Maybe not but really worth looking into...

 

I'm kind of dreading and already half expecting the cat. interesting in your thread, as I thought it odd also, was the dicussion on coils all going in one blow. they replaced 3 of mine, I asked if they tested to make sure they were dead and they of course said yes. I'm not so sure they didn't just expect the coils, replace them, and call it a day.

However, I haven't had a recurrence of the mis-fire code so maybe I really did have a whole side blow out. sigh....so much money to spend after 3 months of ownership.

 

What MY?

 

2005 3.0

 

MAF sensor was the missing piece of the puzzle. Is it possible for a bad MAf to cause cylinder misfires?

 

Check LTFT each bank at idle & 2500rpm. Post them here if you want ideas.

Cheap OBD tool with live data like elm327 is all you need. A few $$$ only.

 

JagV8 is right on here!

I resisted getting a ELM327 but finally did. That thing can do a lot for very little cost.

In fact I am about ready to get a Bluetooth version to get rid of the wires.

They are too cheap to not have one. Beats running to the parts store to get the codes read!
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Yes... Do what they are saying regarding the scan tool. This is true for any modern car. That tool alone is now just as important as a basic socket set. Even if you don't do the work, just having the "true" data when talking with a repair shop will pay for it...

Think.... CarMD ... That is really all that over hyped infomercial device is...

And, yes a MAF sending the "wrong" data can cause all kinds of goofy things, like miss-fires. But, even a small air leak can cause symptoms that resemble a failing MAF. More the reason to take the diagnosis part very seriously....

 

I was more concerned that the dealership saw misfire codes, yanked 3 coils and plugs and replaced them, and it wasn't necessary. No real way for me to prove anything even if that were the case as I don't have the old plugs and coils at all.