Mr Missfire

[chetzar]

Well, just shortly after getting my charing system running again (thanks to everyone who helped me figure that out) I now have a cylinder missfire. i've been working on this for the past few days and kinda hit a dead end today for anything to try before taking it to a shop and have them tell me its a valve.
I tried:
Plugs
Plug Wires
Cleaned IAC/TB/Ports into the Intake manifold from IAC
Fuel Filter (after getting rust in my eye, causing it to get scratched)

So anyone else have any ideas of what it could be other than something mechanical? I get no CEL, Oil Level is good (pressure gets low sometimes, but not often). If I take it to a shop, and it is a valve, how hard is it to replace? I'm guessing it requires a teardown of the entire top of the engine, but how hard is the teardown?

Edit:
Forgot to mention, we did use a timing gun to make sure all the wires/plugs are firing. Hooked the pickup up to each wire and checked it two or three times to eliminate the coil pack/wires/plugs.

 

[rileyrs]

run a compression test on all cylinders, just to know which are functioning best.
if all seem relitively ok, its probly a valve, in which case top end teardown is in order.
ive never done one on the X, so im not sure how hard it is, but i bet you could find a good write up on here, or at least use a haynes manual. and if you have general engine experience, you should be able to handle it.

 

[Blacksheep Josh]

Double check to make sure the plugs are all in secure, and that NONE of the plugs are crossed. When I last changed my wires I accidentally crossed a wire and had a horrible misfire problem.

 

[chetzar]

I found out this afternoon that my dad has a compression kit, so tomorrow after work I'll do a compression test and report back. And I will double check my wires but seeing as I did one wire at a time I think I got them all in the same as they came out.

 

[wangmauler]

any luck with that as I am having almost the same issue...

 

[Blacksheep Josh]

Definitely worth double checking... I was positive I had done mine right (had to take all off at once to exchange out) and I messed one up. Wasn't until I looked at a Haynes manual was I able to figure it out. The coil pack and engine are not the same "alignment", they're different.

 

[BlakeOfDoom]

Seriously, check your wires, I was stumped for a month after a head replacement until I took it to a shop and they me my wires were misrouted.

 

[wangmauler]

the issue i'm having right now with mine, is every 4 or 5 months or so, my cyl 5 will missfire unless i replace the spark plug, but if i move the bad spark plug from cyl 5 to any other, (with the new spark plug in cly 5), it works fine. wires are fine, tried everything except the compression tests, which I will do tomorrow/this weekend. I'll post my results here!

 

[wangmauler]

Okay so my results were not as I thought they were going to be. All 6 cyl tested within 9 PSI of each other, lowest being 159PSI highest 168PSI. Just for testing I added oil in each cyl and reran all tests and saw almost no increase in psi. One of the cylinders increased 2 PSI but it was still only 166 at that point.

I have tried spark plugs, new spark plug wires, new coil, and this test, and nothing seems to help it out.

If I run my check engine code, I get Cly. #5 Missfire. thats it....helppppp!!!

 

[wangmauler]

anyone¿

 

[BonesDT]

What about the fuel injector?

 

[wangmauler]

**UPDATE** Had a 3 different mechanics look at my issue, they ran leakdown tests, dye tests, replaced a few parts including the fuel injectors, I forget the rest(wrote it down somewhere, looking), but still the same issue - All the mechanics are stumped as to why i'm getting to missfires...should I just break down and bring this thing to FORD? lol.

 

[BonesDT]

What exactly do you mean by "missfire"? Can your engine run at all? Is it running very rough and shaking and very down on power? Or is it just what you are reading on the scanner?

I scanned my comp once when my engine was healthy. I got a "missfire" code. I ignored it.

I think I experienced a true missfire a month ago. My engine idled very rough and I could barely maintain highway speeds. I felt a noticeable power loss and I could see my stick shifter shaking at stop lights. It actually went away on it's own, but I drove until I was near empty, then dumped half a bottle of Sea Foam in the gas tank and the other half in the vacuum hoses. Drove around until I was deathly empty then filled up a little with Premium (I found the 87 around me def clogged the carbs on my bike). Then did new spark plugs & wires and everything is AOK.

So ... if it's just the code, I would ignore it (unless you can't get inspected, but I'd still ignore it and pay a shop off to give you a black market sticker). If you are truely experiencing a missfire, try the Sea Foam treatment. I'm not too sure how effective it is, but I'm pretty sure it can't hurt.

I also HIGHLY recommend Redline's FI/Carb cleaner, I forget the actual name of it. I used that on my quad-carb'ed bike that the engine would barely turn on. In about 1 min it ran like new and hasn't had a problem since.

 

[wangmauler]

My engines definitly getting an actual missfire - feels like its running on 4cyl, I'm having the same issue as you were having - can barely get up hills, but it is still running. Very rough shaking idle. I'll try the seafoam this weekend see how that runs.

 

[wangmauler]

andddd my entire exaust from the rear of my truck to the cat. converter just fell off. andddd my truck got broken into, apparently both doors and the rear door lock, but the back window does not.

Time for a new vehicle I think. gotta 2001 explorer sport lined up, hopefully I'll grab that!

BTW that seafoam didn't seem like it did anything - probably because my issue with the misfiring.. anyways, new vehicle upcoming!