PLEASE HELP..Bad misfire and feels like only running on 5 cylinders (I searched )

[FHP89LX]

**UPDATE ON POST #13** PROBLEM FIXED!

Hey folks, I own a 2000 Explorer 4.0L OHV. It has 172K on the clock. I use this vehicle everyday. For about 1 month I have been getting trouble code PO305. (misfire #5). I replaced #5 plug but the problem was still there. I tried Lucas Fuel treatment, one full can of Sea Foam, and it still has the misfire.

Sometimes the motor will smooth out and but then it will misfire again when the motor cools down. So I went ahead and replaced some parts like:

I bought a Felpro Kit (Part# MS90732) for the intake gaskets. It came with the Upper (plenum) gasket, fuel rail, and EGR Tube O-Ring.
I replaced all wires, coil, plugs (plugs are 6 months old )
I replaced #5 plug with a new one 15 days ago because it kept giving me PO305 code.
I replaced #5 injector
I did a compression check and pass.

I am still having a really bad misfire like if the truck is running on 5 cylinders and I cant barely drive the truck.

I removed #5 & #6 plugs just to see how they look. They look really bad I think. Can anyone tell me what is causing this? Will this cause the misfire and force to truck to run or feel like its running on 5 cylinders?

I use this truck everyday and it's all i have. I had to cancel my vacation trip because of this problem. Ive been working on this truck for 4 days now.

Please help. Thank you.

 

[robertoa1a]

Rich mixture. Are the plugs wired to the correct coil. Maybe clean the maf.

 

[akarro]

Hey

I had misfire in all of one side cilinders. It was not very bad but getting worse.
I changed the sparks and cable no effect.
I had a chance to lend a ignition coil pack from other explorer. I really don't recognize my explorer any more, very smoot idle and a lot of more power
Yes the MAF can cause it also, because then the fuel mixture goes wrong.
I ha a chance to buy a new one, but it did't helped lot.
I have once messed up the cables, result was like driveing old russian Lada.
But if it has gone worser from time to time, maybe you should look to ignition coil pack

Hopefully there where something useful in this text.

 

[33exploder]

the spark plugs look like there is too much anti-seize on the ends. you should only apply it up to the 2nd thread from the end.

cyl 1 & 5 are on the same coil pack.

the PCM (eec-v) and the EDIS ARE INCORPORATED into one unit. pull out the PCM cover located @ the right kick panel and connect a breckout box to test the PCM. the pcm will never tell on it self.IF THE PCM IS bad, whatever cercuit that has a problem inside the PCM, THE PCM well point to that sensor and not to PCM.
IF you ****inue to look at the sensor rather than the PCM you will be chaseing rabbits all day. good luck.

 

[33exploder]

check out this post:
http://www.explorerforum.com/forums/showthread.php?t=248036

 

[robertoa1a]

Sounds logical captain.

 

[FHP89LX]

Hey

I had misfire in all of one side cilinders. It was not very bad but getting worse.
I changed the sparks and cable no effect.
I had a chance to lend a ignition coil pack from other explorer. I really don't recognize my explorer any more, very smoot idle and a lot of more power
Yes the MAF can cause it also, because then the fuel mixture goes wrong.
I ha a chance to buy a new one, but it did't helped lot.
I have once messed up the cables, result was like driveing old russian Lada.
But if it has gone worser from time to time, maybe you should look to ignition coil pack

Hopefully there where something useful in this text.

Well, just for the hell of it i re-installed my original coil pack and i dont know but I think it run 5% better. Still has a very bad misfire like if it's only running on 5 cylinders, but slightly smoother on park and rough on drive. maybe its all in my head.

You guys think it could be the coil pack? and to make it worse the plugs and coil pack combined?

Tomorrow I will buy cleaner for the MAF and see if that helps.


As for 33explorder Those plugs were installed six months ago. I never used anit-seize on the plugs. I know I should but i didn't.

 

[robertoa1a]

I doubt it. A rich mixture. Carbon deposits. I wonder what the odds are of having a crank position sensor or something. Were all the plugs like that? I'm about to agree that there is an engine management issue of some sort. I'm not sure if you should clear your codes or not but did you reset your computer?

 

[FHP89LX]

I doubt it. A rich mixture. Carbon deposits. I wonder what the odds are of having a crank position sensor or something. Were all the plugs like that? I'm about to agree that there is an engine management issue of some sort. I'm not sure if you should clear your codes or not but did you reset your computer?

I only removed two of them today. I was going to pull all of them tomorrow and see how they look.
All the codes cleared because I had the battery unplugged. The only code that I ever had with this issue was PO305-misfire #5.

I was thinking of replacing the coil pack and plugs, what do you think?

What will the crank position sensor cause if it goes bad?

I also notice my oil level is way pass the full level mark.

All your help is appreciated. I’ve been trying solve this for four days now.

 

[robertoa1a]

you could use a cheep spark tester with the lead with the boot on the #5 coil and the #5 wire completing the circuit and watch the spark. I seen mechanics do it with a screw driver but that coil can shock the ---- out of you. This is kind of one of those problems where I wish I could loan you my tools and books.

 

[ranger7ltr]

Have you pulled the valve cover yet?

When I first bought my 99 Explorer Sport, it didn't run and after some serious work got it to run pretty well.. I cleaned the engine up and then got a dead misfire in one of the cylinders... I did as you did[Seafoam snake oil, plugs, wires, coil pack, etc] only to not get anywhere...

I decided to run a compression test and it was great as well.. So for grins I pulled the valve cover on the side that had the miss and found the intake pushrod laying on the side of the exhaust rocker and not opening the intake valve.. Now the plug in that particular cylinder was a bit oily and wetter than the others but looking at the plug you pulled out I am thinking maybe you have an exhaust valve burned or not opening and the buildup on the plug is coming from the burning but none of the fuel escaping from the cylinder...

I know a fuel/ignition management problem would be easier to deal with but this is what I ran into.. BTW, that was 5000 miles ago and the pushrod hasn't come back out yet...

Good luck and let us know what you find out...And hopefully you don't have a blown head gasket problem....

 

[FHP89LX]

I think I will replace my coil, wires, and plugs. I have lifetime on the wires so I will exchange them and see if all this helps.

 

[FHP89LX]

**Update**

Well, with all the headaches, cuts, rain, 94+ degree weather, humidity, removing the upper intake and fuel rail 3 times, and cancelling my deserved VACATION!, she is finally ALIVE!!

I replaced the ignition coil, wires, and plugs and now my truck runs smooth. All the plugs looked the same as the pictures above except for # 2. It was kind of loose and still looked new. I spent almost $200 on everything. Nice, that money was for my piña colada's in the Bahamas. Till next year then.

What a nightmare. I thank all of you that helped out with this problem

 

[robertoa1a]

Congrads! Sorry about the frustration. I thought Jacksonville was hot.

 

[Arvika]

**Update**

Well, with all the headaches, cuts, rain, 94+ degree weather, humidity, removing the upper intake and fuel rail 3 times, and cancelling my deserved VACATION!, she is finally ALIVE!!

I replaced the ignition coil, wires, and plugs and now my truck runs smooth. All the plugs looked the same as the pictures above except for # 2. It was kind of loose and still looked new. I spent almost $200 on everything. Nice, that money was for my piña colada's in the Bahamas. Till next year then.

What a nightmare. I thank all of you that helped out with this problem

I have the same problem, missfire on cyl 2, 3 and 5 when I check the faultcodes. Do you think that the coil is the big problem?
I did replace the plugs, they looked nice but I had to start with them.
My intake is also fixed after a leaktest with startgas... The seals where rockhard.

 

[FHP89LX]

I have the same problem, missfire on cyl 2, 3 and 5 when I check the faultcodes. Do you think that the coil is the big problem?
I did replace the plugs, they looked nice but I had to start with them.
My intake is also fixed after a leaktest with startgas... The seals where rockhard.

How many miles are on that coil and wires? The last thing I did was I replaced my coil, wires and plugs and the truck ran great again. Since you changed your plugs and intake gaskets then It could be your wires & coil.

I bought everthing at Autozone because I get lifetime on the wires and I can replace them for free if they go bad. I already had new wires on my truck but I replaced them anyways. I guess my problem was the coil at the end. Make sure when you re-install your wires that they go in the correct fireing order.

 

[robertoa1a]

There is a welth of people here, including some engineers. When you check a problem, use some descretion, and make sure you are thurough. You can get all of the advice you need.

You have to do your homework too!

 

[not_so_special_e]

Howdy - a quick question...

I know this post is old, and not sure if original poster is still around, but I was wondering if O.P. or anyone else had this problem, and if so, did your symptoms sound like this...> This is a 1998 Mercury Mountaineer (SUV)

....it runs and drives and everything works....just the motor started running on five cylinders. I parked it after driving it home and it was making a knocking sound.

Would what the original poster posted cause these symptoms?

Thanks in advance for any reply!

Have a great day everyone

 

[not_so_special_e]

Did the misfire...

Howdy,

Did your misfire create a terrible "knocking" noise...especially when cold? I mean a LOUD one, almost like an exhaust leak? The knocking noise gets less loud and more intermittent when it's ran a few miles and warms up.

That's what's happening on this 1998 Mercury Mountaineer

Thanks! Cuz I have what I believe to be a misfire(believe it's #5 cylinder), but it knocks LOUD!

Thanks!