Misfire Help 02 GT CEL Flashing
 

Ok this may be little long but I am going to try to get all the details, and see if someone can give some advice. I have a 02 GT coupe manual, and I have has some weird misfires, but let me start from the beginning. When I purchased the car the previous owner deleted the cats, and due to regulations to get inspection I had to add them back so I purchased some Flowmaster high flow cats and had them installed, right before I did I had a CEL that read P0300 and P0301, so at first had it removed with scan tool due to just trying to get inspection, well it never showed back on cylinder 1 but later about a week later it showed up on cylinder 2 and still with the P0300 so I pulled the plugs from the COP and the engine died down so I moved spark plug from 2 to 1 just to see if it was a bad plug and reset again. After that about 3 days later I had the cats installed and did my driving to getting systems ready and passed everything just fine. Since I had drove the car for about 2 weeks granted I dont go that far and its not a daily driver, so I noticed that my idle sits around 650-700 rpm, but would start around 900-1000 and then just drop to that point and seemed a little off, but drove great for the most part, maybe a little power loss but nothing drastic. So i decided to pull the IAC off and sure enough it was full of carbon gunk, and I noticed that my PCV valve hose was collapsing, so I cleaned the IAC, put new PCV and new hose on and that fixed the collapsing, and then engine seemed to idle better but then got back to that 650-700 range, and seems a little off at idle but not really bad. So I take it down the road I am driving and I got into it, and my CEL was blinking, and this has now happened twice, and I get back to my driveway hook up the scanner and I am getting P0303 but I seemed to have fixed the P0300 as that has not come back, but the weird part is when I get this flashing and that code when I turn my car off let it sit a second and cut it back on the code is gone, and no CEL, and it only does that flashing when I got into it, and cut off when I let off after about maybe 15-20 seconds, I have switched around COP to see if code would show up elsewhere and it has not, I also have changed plugs, and I just added some fuel injector and valve cleaner but that is still doing its thing as my gas tank is still pretty full. I also notice that I am putting off a little of a burn smell from the exhaust but dont know if that is the new cats breaking in, its not real bad burn smell but just noticeable and after getting car to normal operating temps. I also have no over heating, and oil looks fine and oil gauge. I was just wondering if someone can help me out here that may have had this experience before, or point me in the right direction, I will probably have compression test done soon as well. Sorry for such a long post just wanted to get all details in. Thanks.

the po300 is a random misfire....ignore that code, the p0303 means that cyl number 3 is missing, i recommend at the minimum replacing the coil and plug on number 3, (passenger side 3rd plug back). even better would be to replace all plugs, and any coils on cylinders that have flagged misfire codes. the smell u are getting from the exhaust is caused by the cats burning up the fuel that didnt get burned due to the misfire. since the miss is not happening all the time, you can hold off on the compression test. all that you describe indicates an ignition concern.

Thanks jwogg for the response, I did replace all the plugs yesterday the only reason I have not replaced the coils was due to moving 2 other ones to that cylinder even 1 from the other side just to see if the code would move and it didnt that is what is confusing usually it will move the code to the other cylinder when you move the COP.

regardless, you posted that the miss moved i would suspect coils, these are the ford DG508 part number and i have seen several cars and trucks that run them have multiple coils go bad, sometimes they only miss under the right amount of load, and may only miss when hot. typically if you had a compression related misfire, it would miss either at idle and go away as rpms are raised, or it would miss at all times.

ok see what you are saying and by the way I have the MSD COP which i heard can crap out quicker than OEM

yeah, i would switch back to oem coils, you can get them for $37 per coil off of amazon, and no matter what anybody says, they are the best coil to run.

WOW!!! Thanks for that heads up on the Amazon they were going to cost me almost $600 for the set at Advance and AZ

yep, just make sure that they say that they are DG508, and not an" oe quality coil", the $17 coils are china junk, the $37 coils are ford coils new sealed in bags

Hey jwogg just wanted to give you a heads up on something and for anyone reading this, I went to Amazon like you told me and sure enough they have them on there for like $37.36 the only thing that worried me was that one of the answers in the questions was they did not come with boots, so i kept researching and was looking on Summit's site and found the same OEM DG508 Motocraft of course they were $49, but I found this thread and someone mentioned that Summit does price matching so I called Summit and the rep said yes sir we price match and will beat the price by a $1 so they let me get them for $36.36 and that is with the boot. So a heads up if anyone finds something cheaper on Ebay or any other site, but are worried about shipping or just want to order from a big reputable parts company Summit will price match.

thats cool, just so you and everyone else knows, i have ordered them from amazon and they DO come with boots and all just as they would from the dealer, and are even sealed in a motorcraft bag.