This afternoon I got an RP that lasted for about ten seconds then went away (occurred within 3 minutes of start up) but no noticeable performance issues as I drove 25 miles to have dinner with the daughter

On the way home, this time immediately at start - received the RP and the CEL came on minimal hesitation, but cleared with the RP. CEL remained on

Got home and checked codes

P0300, 0301, 0302, 0303, 0305, 0306 and 1316 - Random misfires, misfire on 1,2,3,5,6 and misfire excess emission. All coils and plugs were replaced about a week ago. So any words of wisdom???

 

OE coils? I ask because non-OE on S-Types frequently seem junk.

Or maybe disturbed wiring.

 

JagV8, sorry, should have included that the codes had cropped up twice before without the CEL (once about 6 weeks ago, then about 2 weeks ago). The first instance, I had 7 of 8 cylinder misfires with the 1316, the second time was the exact same codes listed in the first post.

The coils are made by Prenco purchased off of e-Bay (found a thread here on the forum recommending them). But that could still be a possibility and since I haven't disposed of the originals, could do some swapping.

 

I also like coils as the culprit but, as the instances are happening several weeks apart (and presumably longer than two 'trips' after clearing the codes), is there any chance of poor fuel quality?

Graham

 

Would timing i.e. tensioners etc be a possibility?

 

The P0300 has several causes and for you to get all cylinders misfire after the replacement of all plugs and coils I would be looking into the fuel presentation. I would check the fuel pressure and filter to see if they are a problem. Along with that I would add BG44K to your fuel, it could be that you have sticking injectors or bad fuel. You can check the injectors by using a stethoscope and listen for a chirp should. At the same time clean the throttle body.

The P0300 also can be created by a failing ignition module or an incorrect gap on the plugs. When you replaced the coils did you do a hard reset??

As a side note I have used aftermarket coils in both my Jags with no ill results.

 

guys - thanks for the replies, looking at the possible causes, I was wondering if the fuel filter might be suspect (assumed to be original). Have not checked fuel pressure but will and while I have been using Lucas treatment every so often, will try the BG44k. I did purchase a fuel filter last year, just haven't gotten around to replace but will look further into.

yes did a hard reset prior to replacing plugs/coils. I did not check the plug gap as they are supposed to be pre-gapped. If the fuel prospects don't pan out, I can look here as well.

 

Also there is a coil failure mode where one or two bad coils can cause multiple misfires. I would clear the codes, then run until first sign of RP/CEL, then immediately stop the engine and read the codes. Usually the first one or two fault codes that appear are the real coil faults.

 

steve - appreciate the insight!!! I did clear the codes, so will look at a few things this weekend and if it returns before I get to investigate, will follow your guidance.

Something else that may or may not matter - this has never occurred from a cold iron condition. Every time has been when I have shut the car off for a brief period of 5 to 30 minutes and shortly after starting back up (usually within the first few minutes of driving) the RP pops in. Codes checked at destination have been the misfires. Next time - should there be one, I will immediately check

 

didn't get a chance to look at fuel system over the weekend -spending time with the daughter who is home from college, but this afternoon after I got home from work, went out an hour or so later to run an errand and car acted like it was going to stall. Gave it a little gas and it settled down, but immediately gave an RP (no CEL) as I started out the drive. Stopped and checked codes found a 300 and 1316. Will start looking at fuel system this week

 

I had prior problems with cheap spark plugs in high performance engines. Mis-fire codes at a minimum. Could that be part of the problem as well? I've used nothing but iridiums since - no problems.

 

hope not the plugs as I put Bosch Iridiums in (replaced ngk iridiums) but not outside the realm of possibility. Really thinking along the lines Gus, Graham and Steve (WhiteXKR) have mentioned with something along the fuel delivery. Hopefully get to look at it more this weekend