the codes are likely P series codes ie P0304 and P0308
simple easy - the PCM sees a misfire on those cylinders- #4 and #8.
BASICS is there spark at those plugs- are the injectors pulsing a 'NOID" light will make quick work of that ck...
a fuel pressure check AND a fuel pressure leak down will help checking fuel injs, finally a compression test.
Sorry, grand marque, and I put my bluetooth scanner app on it and for some reason It is showing boost on accelleration. And no it doesn't have a turbo or a SC. Only thing I dould think of is if it is pumping exhaust into the intake if that is possible.
For some reason I've never had these problems on my 65 pickup
Oh and I'm gonna wait til tomorrow to check it out, we've been hovering in the low teens the last few days, suppose to be 40ish tomorrow. I was just trying to get some knowledgable insight before I go snooping around.
I do have a noid set so I'll go there if I don't find something else first.
I've never really watched a vacuum gauge while I was driving before unless it was a turbo or SC car, so I'm guessing the only possibility is some type of EGR malfunction if that's possible.
Sorry, I live on Cape Cod, there are more Grande Marques here than the entire state of Florida, it's turned into blue hair city here. You'll have to excuse my slang, by the way did they ever make a Grande Marauder? I thought Marauder was there HIPO sedan?
also i have found on a few ford 4.6L a bad vacuum fitting on the back of intake and it affects the back two cylinders and make them skip easy find with carb cleaner but it could be a coil or a plug or even a plug boot
with 2 cylinders at the same time im leaning to a vacuum leak
that made the most sense to me, I gave it a quick glance yesturday but it was freekin freezin out there and that engine is tucked under the firewall so I couldn't see crap. Unfortunatly I have a run tomorrow to Conn. for a load of stone, so I'll have to look at it Saturday.
OK, couple of things happened, first I didnt' get to it until this morning, and the temp is now 55 degrees out.
When i scanned it this AM it only came up with the #8 cyl misfire. So I swapped out 7 and 8 coils and just for the hell of it I also swapped 3 and 4.
the skip did move to 7 so I replaced that coil and at the moment all is well.
I'm guessing the temp may have something to do with it so I'm expecting # 4 skip to come back,(it's actually in #3 now). But I had to pay 69.00 bux for the coil in town so I just bought the one , and ordered a pair of them from Rockauto for 31.00 each to put on the shelf.
OH and just fyi, when I swapped out the coil and cleared the codes, I had to drive it about 15 miles before it showed up on 7, although it was skipping all the way. I would have thought it would be a lot quicker but I guess not.
"I had to drive it about 15 miles before it showed up on 7, although it was skipping all the way." I hate when the PCM is so reluctant to set a code. Sometimes it is faster to disconnect a coil and run it to see if you can tell the difference between one bad cylinder or two.