New to the site. Have a 2000 F150 4.6L 4X4. It used to do this almost all the time a couple years ago then stopped, until yesterday. After a hard rain it starts missing really bad for about a day, service engine light comes on. I didn't drive it at all the day it rained hard, today it seems to be running fine again, exactly what used to happen. I plan on taking it to the shop to see what the computer says but was hoping one of you people knows what's going on.
Tahnks

 

Do you have a CEL or MIL on ? Has it ever flashed/blinked ?

 

coil got wet, you must have gotten lucky and it dried up

 

I'm mechanicaly stupid
jbrew
What's cel or mil?

az
Where's the coil, how do I protect it and how did you get a picture of my wife and girlfriend

 

i believe on the 2000 4.6 it used coil packs and not the coil on plugs, which means they will be right in the front of the engine with a bunch of wires coming off of them there will be 2 coils

 

a CEL is a check engine light. MIL malfunction indicator lamp.

Yea, I think it's the opposite lol- you probably have a COP system Coil Over Plug, but in 2000 some had coil packs. You have to look. If you have plug wires, you have packs.

 

I had a similar problem a couple of years back with my 99 F150. I thought is was the coils b/c that is most common but turns out the last oil change I did was done with Grease Monkey and they didn't return my dip stick to the proper position, failed to tell me and rain got down the hole and eventually siezed my whole engine up. Needless to say, I don't go to quick lube places anymore.

 

I had the same EXACT problem in my 97 4.6, finally it set a check engine light. I started poking around under the hood but found nothing? I went and got a spray bottle and squirted the coil pack on the right bank and it lit up like the 4th of july! Turns out the coil pack had a hairline crack in it. 50 bucks and 10 min later I was back on the road.

 

Same thing happened to me on my V-6 at 84k. New plugs and wires did not fix it, it did turn out to be the coil pack.

 

Appreciate all the returns, no plug wires so it sounds like I have COP system. Again never drove it the day it rained hard, the next day as soon as I fired it up it was missing bad. Because of COP system are you still thinking coil. Is this an individual coil over ea. plug or? and should my local mechanic be able to spot which one or side, anything I can do to help figure it out.
Thanks all

 

Get the code read, it should tell you which cylinder the miss is on.

I just had a similar issue with my 97, and it turned out to be moisture in the #3 plug well.
It allowing the spark voltage to track to ground.

I took it to the guy I use when I can't handle a repair or don't have the time to do it myself.

About $50 and a new plug later I was out the door.

Had I had time to pull the plug I would have found it myself.
I checked the coil pack, and the plug wire, but I didn't have time to pull the plug.

The mystery is how the moisture got into the #3 plug.....

The COP system is individual coils on each plug.


In your case it could be a bad coil, but also check for moisture in the plug wells.
Especially #4 & #8.

 

How many miles are on it? when was the last tune up? Have you ever replaced the plugs? Have you considered replacing the coils? its really not that expensive and it will improve the trucks reliability and performance. You can get a set of 8 coils on e-bay for $80 a set of new motorcraft plugs lots of dielectric grease (to water proof them) and your good to go for another 10 years.. All for about $150.

 

same problem on 2001 5.4.

The rubber seal on the hood got dryrotted because Pine needles were allowed to sit there for a while. After rain water got into the #1 plug well and caused issues.

 

had the same problem on my 00. new plugs are good for nothing unless they are missing. but your problem is the cop. plugs can last a million miles. a simple myth that they "go bad". its very rare that a plug goes bad. put silicon around 4 and 8. ford will charge $70 to tell ya which cylinder is missing. but ONLY while its missing. just in case the silicon doesnt work. worked for me

 

Was out of town for a week+, so just got my truck in yesterday. Didn't get a chance to talk to the mechanic but he wrote on the receipt diagnostic and coil repair, only cost me $45.00
Thanks all