This car just doesn't like going to Petersburg and back. Its a 300 mile round trip. Last time is when the serpentine tensioner failed and it had to be flat bedded home. Today I made it there for my Doc appointment but on the way back about 20 miles from home it started bucking at speed but still idled smooth. After a few miles the Check Engine light came on also. Drove it home and found codes P0308 and P1316 (and P1111). So thats a misfire for cyl #8 the one under the expansion tank. Don't think its moisture because it ran almost 300 miles before it did it and no rain etc, no coolant leaks so it had plenty of time to dry if it had been wet. So I am letting the engine cool off and will swap the coil with the cyl next to it and see what happens. I've had this thing almost a year and a half and I still can't trust it on a trip.

Dave

 

It is a 97 Jag, **** breaks. It is not a Honda.

 

Hang in there and get the maintenance sorted out. They really are reliable cars once done.

 

Maybe it's just an 18-yr old coil that's given up. They're a wear item...

 

Yes I figure its just a dead coil but I am going to swap it this morning and make sure. It rained as soon as I got home yesterday so I couldn't work on it then. Someone in the past broke off the remains of all the connectors and soldered all the coils in. Definitely a more reliable connection but now I have to find an extension cord long enough to get out there to swap them.


Dave

 

I decided to start it up first and of course the problem was gone even though it did it for 30 miles yesterday. So I reset the codes with Torque and went for a drive. Not even 5 minutes into the drive it did it again, same P0308.
I came back home and pulled out the cyl#8 coil. Dry as a bone, no oil stains, no rust, rubber boot looks pristine. Even has silicon grease inside. Swapped it with the one on the other end. So if its the coil the next code should be P0305. That would mean this coil has a problem with being heated up and then it fails. If the code still stays P0308 then its either the plug, ignition amp module or ECU. Something that fails when warmed up. I'll take it out for a drive later and see what happens after I reset the codes again first. To fried from the heat to do it now.
One observation - all the coils are Denso EXCEPT the one for cyl 8. It has no markings at all on it except "PGK" stamped in white, no part numbers nothing. Its made a little different than the rest. Maybe its just a crappy aftermarket part and its in the worst position for heat and moisture etc.


Dave

 

Sounds to me like you have one sorry aftermarket coil that is causing havoc. You know how tempermental these coils can be once they get some age and miles on them, especially the off-brand (or no-brand) ones....

 

Figures, drove it until it did it again and now my OBDII reader stopped working. Wont connect to the ECU anymore. So now I don't know if the code switched cylinders. Guess I'll just order a new coil and if that doesn't fix it by then I should have a new code reader.


Dave

 

"Murphy was an optimist"

good luck!

 

Yep, and just before it started doing it I was thinking to myself how damn nice it was running. Because I'd been driving it mostly around town before this trip it started doing the slightly rough idle at stops. Just enough to feel it through the steering wheel. After all the freeway driving it was now idling so smooth you could barely tell it was running. Thats what I get for thinking like that.

I'm need to go grocery shopping today and its my only car so if the check engine light comes on I will stop by Auto Zone and have them read it. They are right across the street from the grocery store. They won't read the codes unless your check engine light is one. I was able to reset it last night before the reader quit working. Was just a $10 cheapy bluetooth. Guess they are only good for one use.



Dave

 

Welp, glad I didn't buy a coil.
After I swapped the coil with cylinder 5 I took a drive to the grocery store. It ran fine for about 2 miles and then gradually started missing and bucking. First just barely and eventually worked up to pretty much a dead miss. After I got home I checked the codes. I found if you bang on the $10 Bluetooth reader it will work briefly. Must have a bad solder joint inside. So I was expecting to see P0305 but guess what? Its still P0308 so its not the coil. And its a heat problem as it runs ok when cold. Doesn't sound like a spark plug problem so that leaves the Ignition amp module or the ECU.
After the engine cools off I am going to swap the Ignition amp modules and see what happens. If still the same code then the ECU goes back to ASI. Should still be under warranty.



Dave

 

Not sure that I would trust a cheap code reader that I had to bang on in order to get a reading....

And I've never had the guys at Autozone or Advance Auto Parts refuse to hook up their OBDII code readers to our vehicles simply because no MIL was illuminated on the dash. I would question that policy if I were you....

 

I'm also worried about damaging the cat for that side from the raw gas. Its a bluetooth reader and using Torque to read it. I just reset it and drove it again and code P0308/P1316 reappeared along with the MIL. The suspect coil is in cyl 5 position now so its not the coil. Doesn't seem likely a spark plug would only fail when warm. So I'm guessing its the Ignition Module or ECU. I'll know tomorrow when I swap the 2 Ignition modules and try again. I also have a new reader on order but wont see it until next week. If the MIL comes on again I will go to Auto Zone and see if their reader agrees with mine. The Auto Zone here told me they will only code vehicles with an MIL on.


Dave

 

I would suspect the Plug .

 

I'll try swapping the plug before I swap the Ignition module. Its funny that it runs fine for a couple miles and slowly starts failing as it warms up. More like a electronic type failure but who knows....



Dave

 

Less common, but could also be a sticking fuel injector.

 

I'm hoping its not that but usually when a FI sticks its not temp sensitive. The car runs great when cold but after a couple miles of driving the miss slowly creeps in.
I was going to change the plugs today but realized I don't have the tools to get the suspected bad one at cyl 8 out. I took the 2 bolts out that hold the valve in thats in the way but it didn't have enough play in the hoses to move it out of the way to get the plug out. I need to get a swivel socket (or a u joint) to get that plug out so it will have to wait.


Dave

 

I gave up on the Jag for a while as I had to do some house repairs ahead of a realtor showing my house.
So far all I have done was swapped the coil from cyl 8 to cyl 5 and check connections, vacuum hoses etc.
After swapping the coil and clearing the error I took it for a short drive. As the last time it ran fine for a mile or so and then the miss slowly faded in until it was pretty much a dead miss. Errors came back same, P0308 and P1316. So that says it ain't the coil. I was also having trouble with Bluetooth reader working reliably.
So, today my new reader arrived. I bought a different brand and a 2.1 version this time. Old one was a 1.5 version.
So as I had cleared the codes and not driven it since the last session I took the car for a short drive again. Same symptoms. Runs great for a few minutes and the miss slowly fades in as it warms up.
So I check the errors on Torque Pro with the new reader. Now I get P0300 and P1316. So now its a random misfire. So the old reader might have been sending me after a red herring with the P0308 code.
So if its random and heat related then its either the ECU, a vacuum leak or a fuel problem.
Anyone have any other insight that might help?

Thanks,
Dave

 

After it cooled down I cleared the codes and took another short drive. The problem is so repeatable it starts doing it when I get to a certain intersection each time. And now the code is consistently P0300/P1316 every time so I am convinced the old reader was B'jorked so its always been random misfire and not cyl 8. The way it slowly fades in seems to point to a electronics problem so I guess I need to send the ECU back to ASI. I don't think a fuel pump would act like this and the fuel filter has less than 1000 miles on it.
I also took off the air hose between the MAS and the throttle body and examined for leaks and its fine. Also cleaned the plastic piece that goes in the valve cover. I also replaced the air filter but the old one looked almost new but I replaced it anyways. No signs of oil in the filter or MAS hose etc. There were the remains of an old wasp nest in the air cleaner box but it wasn't restricting anything. I also tried replacing the rubber mount for the filter box but whoever put the last one in cross-threaded it and as soon as I turned the lower part it snapped right off with the threaded part broke off flush with the fender. I also checked all the harnesses to the coils and injecters and all looked good.


Dave

 

Please keep us informed. I hate to think that a ASI repaired ECU could be failing already.