UPDATED 06/19/2011

2000 E250 w/5.4 gas motor, 245K miles, recent new plugs & COP's. Initial start up after sitting all night in cold weather runs fine for a few seconds before a noticable miss occurs, CEL comes on. Turn ignition off, restart immediately and the miss has disappeared. During the day frequent re-starts never has the same thing happen.

Codes tend to be P0352 etc etc but all connections at the COP's are solid, not contributing to this misfire. I'm wondering what else in the ignition wiring I can check for a possible loose connection or failing plug. The most curious thing is how cold weather seems to cause this most often and restarts the same day don't experience the same events.

Any ideas or suggestions would be greatly appreciated.

 

What brand of new COPs did you put on it?

Just asking because I tried a set off ebay and had the same problem with one of the new ones.

 

This condition isn't about the individual COP's as I've tested each one and they're all functioning properly. Granatelli were used but they are not the issue because:

a) the problem goes away upon simple restart of the van

b) error codes will show different cylinder misfire numbers each time the codes are read and erased, never the same.

 

May have no relation but I had a screwy miss on my 97 5.4 van but only at highway speeds and very intermittant. It was the vacuum break on the fuel tank sticking closed and pulling the tank into a deep vacuum than opening all the way and losing vacuum. $35.00 fix. Not sure if screwy vacuum readings will throw the manifold sensor off and cause missfires. Mine more shuddered than missed. Point being is vacuum remaining constant?

My Ford dealer was so entralled by the shudder thet kept my van for two days trying to solve it and ended up not charging me anything because they got a huge learning curve as it was the first time they had ever seen it. Cost me a tank of fuel though.

Mikey

 

That's an intriguing idea Mikey---thanks! It would make sense in a way since this happens mostly after sitting all night during the cold, never recurring throughout the day when restarted. When it does happen shutting down then restarting immediately seems to cure it.

Where is this vacuum device and how does one test it properly?

 

The electrically operated solenoid valve is on the frame or fuel tank. It is right behind it in easy acces and view you do not have to drop the tank. It has a two wire plug and one vacuum line to it.

It is not just open/close but operates off a voltage curve to adjust vacuum in the fuel tank and consequently the manifold via the vacumm lines. Mine would stick at low voltages causing higher vacuum causing higher voltage to the unit finally resulting in it opening but reducing vacuum to much causing the map sensor to go screwy.

Mikey

 

Mikey this gets more fascinating even if it proves to not be the final problem.

Whenever this happens the codes thrown are lean bank 1 & 2 along with various cylinder misfires, sometimes one or two occasionally 7! Nothing else shows up on my scanner.

This morning is about 20*--started the van and it ran just about 15 seconds before the noticeable shudder similar to a single cylinder misfire. Restarting it eliminates the problem and it won't happen again all day.

I'm wondering if a bad code would be thrown for this condition? All along I've been thinking its a loose connection on perhaps the COP harness where it enters another harness---could be I've been thinking or looking in the wrong areas.

 

Codes are nothing more than diagnostic clues not the answers necessarily. My first experience 10 years ago with a coil going bad on a modular motor was it started to hickup slightly at highway speeds in overdrive consequently just kicking it out of TC lockup in overdrive for a second or two but not really missing. I was told the code was the torque converter failure so I let my trans guy replace it. Drove it out and it did the same thing. Trans guy said too bad no refund for the misdiagnosis must be a wiring harness issue. I said you're not cutting apart my harness on a witch hunt, lawsuit followed after I figured out it was a bad coil. Anyway point being when a plug missfires and % load raises in the EMC the TC unlocks, lesson learned. Oh yea, lost the lawsuit too, again lesson learned.

When my 97 shuddered it would code the final O2 behind the converter not the front O2's on either bank, go figure. It took my Ford dealer two days to solve it. EGR's do the same thing occasionally they can stick momentarily and then run fine for weeks. It takes 5 minutes to pull an EGR spray it with WD40 and make it work again for another 10K miles, besides they are cheap. Seen that movie too.

Mikey

 

Interesting I am experiencing the exact same problems. I have a 00' F250 with a 5.4 and I replaced all the plugs and COP's a few months ago and the problem is just getting worse now sometimes it doesn't go away when I restart it. I used Granatelli COP's too and now I am starting to wonder if they are the problem, I may go back to the Motorcrafts and see if it goes away. What plugs did you use if you don't mind me asking?

 

The Granatelli COP's and Motorcraft plugs # SP479 aren't the problem at all-----there's no need to question them at this point at least in my case. One of the misfires was tracked down to cyl # 7 COP connector not locking properly into place. A simple replacement from NAPA (#EC 259 @ $20 ea) fixed it just fine.

At this point it would seem I have a vacuum leak somewhere in the air intake path. I'm suspecting the inlet duct just forward of the throttle body---warmer weather will let me check things a bit more carefully, probably replacing a few hoses or connections.

HammeredFlat if your problem might be a vacuum leak as well---are you pulling any codes? I got one showing the #7 misfire (bad connector) along with banks #1 & #2 too lean-----the sharp eyes here suggested the vacuum leak possibility.

I don't regret the Granatelli purchase at all----they've performed well for the past year.

 

Yea JWA I got codes lol

p0351, p0353, p0354, p0355, p0356, p0357, p0358 and p0304 and p305

 

Wow Hammered---now that's a buncha codes huh?

Obviously all your COP's aren't misfiring, not if you're still driving that vehicle?

As my own saga on misfires continues I'm more convinced now it's a vacuum leak somewhere in the induction system, more apparent during colder weather. Locally we've had somewhat huge temp swings with some mornings in the 60's and others in the teens. Warmer weather gives me a good idle at start up, colder I'll have the missing problem that triggers the CEL but goes away if I simply restart the van before driving away.

I've already obtained the part numbers and costs for several new "tubes" which include the TB inlet duct leading from the air cleaner box. There is also a smaller "tube" leading from that duct into the left (driver) side valve cover that seems to not fit snugly. Given my van has 248K miles its highly likely one of these air path fittings is in need of replacing.

Having the Granatelli COP's was a good investment or should I say NOT the cause of anything I originally posted about.

 

are you sure it isn't a weak alternator...with a brush hanging up, more so in clod weather....just a thought

how about testing the air temp sensor??

Not to say that couldn't be a vacuum leak....certainly could

 

No its not the alternator----its new and has operated flawlessly since about a year ago. Never heard of such a thing though.........

Don't know where the air temp sensor is unless you mean the MAF?

Honestly this is probably the vacuum leak deal because of other codes I received and having fumbled around under hood noticing how some of the rubber hoses just don't fit all that well.

Good ideas though---have to keep them in mind too.

 

the thought with the ALternater is that as it sits it & cools there is a weak retention spring under a brush, when you 1st start it, or shortly after doesn't set well, therefore not getting correct voltage to all the circuits, giving a rough run symptom ...shut it off and then restart is enough to seat the brush on the alt and rough running symptoms disappear with improved /correct voltage to the system.

Easily verified...when running rough, check the voltage output ...if it is down to 8-11v, it is suspect...if up to 12-14v its good & back to the vacuum hoses

No not the MAF...but it , the air temp sensor (ATS), should be in the same neighborhood as the MAF.

sounds like you need to swap out all the vacuum lines if they all tend to not fit well