I washed the engine down last Saturday and haven't driven the truck since, but today there was a really bad miss, at lower RPM's in any gear under load. even at a stop light, the truck would surge/missfire. I took the truck for a long ride, thinking I got water somewhere it souldn't be and trying to heat the engine up and burn the moisture out, but the truck is still missfiring pretty bad. there is no CEL and I even hooked up my code reader and it says there aren't any codes. so what could it be?

I don't get the fact that with such a bad misfire/surge there wouldn't be a CEL.

thanks in advance....

 

May very well be the crankshaft position sensor - front bottom of engine. The wire harness going to the sensor typically routes under the starter and may be pulled way too tight, causing a bad connection at the plug. I had the same thing happen on my 2002. Rerouted and reconnected the plug, and all was well (also, no CEL, but a really bad miss).

 

Don
check the forum for bad COP. I'v read here were several people have washed their engine and water ends up getting traped around the COP causing a misfire without the CEL being on. I had the same situation where the CEL never came on but had a bad COP.


MP

 

X2

 

a little background here, before I bought the truck, it was stiing for a while, and I'm sure they washed the truck (an engine) to clean it up before selling it. when I first test drove it, it had a miss, not as bad as it is now, but definatly a miss. and there was no CEL either. I had the truck looked at before I bought it and they counldn't find anything wrong, and the next time I went to test drive it there wasn't any miss. so maybe the problem is water got under the COP (last time and this time).

I know how to locate the particular cylinder, remove the connector to the COP and see if the engine runs worse or stays the same. but I wonder if the COP will eventually dry itself out, or if it's ruined??

 

find the cylinder that is misfiring and buy a new c.o.p.

 

I went outside to investigate the missfire and the truck ran fine

I still think something got wet that shouldn't have. what baffles me if that there could be such a bad missfire and the CEL never came on

well anyways it appears I fixed the problem I'll see if it returns in the next few days, but it's running real strong right now

 

It will be back , I guarantee it - It's just having fun with you right now.

It does no good pulling the wires off to see what ones misfiring because you do not have Primary failure yet.

You can stress test it at the dealership - but that 's really a waste of time and money to me in your situation.

Or the next time your truck starts to miss - just floor it a couple times , try to wake up the monitor to get a check engine light.


But heres what you need to do to save yourself 2 years of headaches chasing down misfiring COPs and missing out on that 5.4's power.

Replace them ALL - There only $96 for all eight and it's the best tune up for your ignition system .

If your thinking it runs good once in awhile now , you don't know what your missing......, Yet.

Good Luck.

 

where can I get 8 COPs for $96? I think I might change the COPs and plugs anyways. all the Cop's I can find are well over $200/8

thanks

 

http://cgi.ebay.com/ebaymotors/NEW-I...mZ160144316705

 

I had the same issue happen with me after driving in a really bad snow storm last winter.I had m suspicions on what was wrong so i removed all my COPs and used an airhose and blew out all my plug holes and found out my rear 4 plug holes had water in them and u could see the spark track on them from them missing..i talked to a few ford junkies i know around here and they told me cause they are still firing in the cylinders just a weak spark so it registering as a firing cylinder.Which i still dont get! Cause with all the experience i have workin on Chev's the instant there is any miss u get a code p0300(random miss fire) till it detects more then one or just one plug missing.so i think ford needs to work on there PCM for detecting missfires. Which it should be just a reprogram of the PCM,but who am i to say.PEACE

 

thats what I don't get, the misfire is soooo bad, I can't beleive it doesn't throw a code, but I understand what your saying why it doesn't, it does make sense.

so did blowing out the holes solve the problem or did you wind up replacing the COP's?

 

one more question, I know there are tons of threads on the subject, but which plugs should I use? I'm guessing Motocrafts would work the best, but which ones? platinums?

 

Hey Don i am also thinking it's your COP's.I recently changed all of mine out for the Global Auto ones on ebay and mine runs alot better.
Mine was doing basicly the same thing missing slightly under load but my miss went away if you hammered it.
NEVER wash your engine again
If you can find which one it is causing the problem i can give you one of my originals to put in??My sister lives in Myrtle beach now and is here today so i could send it back with her if you want.
Your best bet is to just replace all of them IMO
Let me know
Kevin

 

Ya the Motorcraft platinums
just a sec...i got the part ##

SP-479
AGSF22WM

those are the plats^^^^auto zone carries them pretty cheap