Brief hesitation/stumble on WOT kickdown

[emig5m]

Two fill ups ago I noticed that if I mashed the gas at 60 where it kicks down there was a major stumble/hesitation that lasted a couple seconds before the motor would take off as normal. It almost feels like a slip/shudder, but if it was just a slip, the motor should rev normal. It was the same gas station I normally fill up at and never had a problem with them before over the years. I did notice there was some water in the tail pipe puddled up (more than I noticed before). Could this be a water in the gas issue? But wouldn't water in the gas make it run crappy all the time and at all rpm?

I filled up the tank yesterday from slightly less than a quarter of a tank from a different gas station and added a bottle of Heet dry gas/antifreeze and the stumble is still there (60 mph WOT kick-down) but not as long as before. I change my fuel filter every two oil changes (a little overkill I know) so I seriously doubt it's that. Like I said, I only started to notice this two fill ups ago and it was pretty bad right after that fill up so I don't know if it's in fact bad gas or just a coincidence with that fill up. What would cause the motor to stumble for a second on a 60 mph kick-down but run fine everywhere else? I thought maybe it was that it was a cooler a damper night, but all my Lightnings that I've owned never had this problem before and I've done kick-downs in 18 degree weather (I know, I know, ka-boom ka-bam rods dangling out of the block - but I'm a 100% stock except for a open air filter).

Could a dirty MAF do this? I think I might of put a little more oil on the filter than before but I always do wrap the filter in paper towels to absorb any excess if present. I hope it's not a torque converter/tranny crapping out. But even if so, the motor itself shouldn't stumble if this was the case, right? Otherwise it starts, runs, and idles just like normal. Is that Heet fuel treatment any good? It would probably take a few fill ups with dry gas to get all the water out anyway if that was the problem?

 

[PhLoBuS]

I had a similar issue and it was because of my EGR.

 

[emig5m]

Thanks. Can it be cleaned or does it have to be replaced? Is the Lightning's EGR the same part number as a regular F150?

 

[03LCalgaryAB]

If you don't have emissions in your state you can delete the EGR. Sounds like a miss to me, maybe 1 of your coil packs is going out? If you are stock I wouldn't be too concerned about the cold weather. When I was stock I would go WOT in -2*c. Most try to stay away from any fuel additives as they can affect your spark plugs. you could check those to while you are at it.

Does the shudder only happen at th 60mph mark? Or any time you punch it?

GL man

 

[emig5m]

If you don't have emissions in your state you can delete the EGR. Sounds like a miss to me, maybe 1 of your coil packs is going out? If you are stock I wouldn't be too concerned about the cold weather. When I was stock I would go WOT in -2*c. Most try to stay away from any fuel additives as they can affect your spark plugs. you could check those to while you are at it.

Does the shudder only happen at th 60mph mark? Or any time you punch it?

GL man

Seems only at the 60mph mark as I took off today from a dead stop burning the tires for a good 30 feet (which I rarely ever do but did it as a test) and it didn't shudder at all from a dead stop to WOT. Although it was barely doing it today at the 60mph kick-down (but was noticeable for a split second). Bad tank of gas that's smoothing out? I'll see how it goes to the next fill up... I'll try the additive for one more tank and leave it alone from there. Hopefully it continues to smooth out and go away...

 

[emig5m]

Would a slipping belt do this?

I jumped on it the other day from a 60mph roll and boy was it stumbling extremely bad. I notice from a dead stop when I let off from WOT after the 2nd shift I can hear a squeal that lasts about a second or so like a belt is slipping. Another thing I noticed when I cleaned the air filter yesterday is that the air intake temp sensor seemed to be leaking in some dirt and grime around it's rubber boot and just swiping my finger across the sensor there was grime on my finger. So I'm thinking about going back to the stock air box and just get a re-cleanable air filter for the stock box - I think the open air filter gets dirty too quick on a daily driver (driving in the rain once seems to do it in) -- I think the stock air box will require less maintenance. Should I just clean the MAF while I'm at it? I actually have an extra MAF on my stock air box as the MAF that's on it now is the MAC air intake kit from my 03...

I also remember when I had a 2000L on loan that I was going to buy that was stumbling very bad the dealer said it was a O2 sensor? Should I just replace mine anyway (seven years old now). Gonna start with the cheapest and/or free stuff first. When I figure it out, I'll post back results.

 

[Youngunn]

Ohm out each one of your COPs, they should all read close to each other, when I had my 2000 Lightning I had one go bad, had miss / stumble like your describing.

Sent from my Nexus One using Tapatalk

 

[emig5m]

Well I have a definite repeatable pattern. Didn't do it all last summer but now that it's cold out again it's doing it again. Seems like it only does it under 50 degree temps (45 out right now). Last winter I took it to a Ford dealer and they couldn't reproduce the problem since they didn't get to my truck until it was already over 50 degrees out and their diagnostics machine didn't pick anything up. They said that they couldn't find anything wrong. What could it be that's only outdoor temp dependent? Would COPs or EGR be outside/air temp dependent if it was the problem? I already swapped out another intake air temp and mass air flow sensor from my old 2003 lightning and that made no difference what-so-ever. Another Ford dealer said that they couldn't even work on SVT vehicles! What the hell do I do if dealers can't even diagnose and fix it? :shrug:

 

[emig5m]

So far I've replaced the MAF, Intake Air Temp sensor, TPS, and EGR. None of those helped although there was some mad carbon chunks inside the intake port from the EGR. Some guy at work said he had a similar issue with his fathers truck and he said it was some sensor on the tranny? (said it was also a temp related issue like me). Gonna have to have a shop check the coil packs because I don't have a OHM meter and don't know how to do it anyway. What I don't get is even if it was a COP, what the hell does that have to do with the temperature outside? If it's bad, it should be bad regardless the outside temp? Now it makes me wonder that since the L makes more boost during colder temps that maybe it could be a bad spark plug or two and under the higher boost they're being blown out for a few seconds? Also, when letting off from WOT I can hear a squeal sometimes for about a second and a half. Still wonder if it could be the s/c belt slipping?

Oh by the way, it's not just on WOT tranny kickdowns, it just seems to do it more intensely on kickdowns. Once that initial stumble is over, it's a normal rocket from there on out until you let off the gas again and then punch it. Fuel pressure problem?

 

[Robert Francis]

If there seems to be a lot of water in the tailpipe, more than what would be expected from condensation, you may have a leaking head gasket or intercooler. Although this would be accompanied by a lowering of coolant levels and I'm sure you would have noticed this by now. COP's don't break down by temp - but if they're failing they do break down under a high load - but as your truck runs well once it does get going under load, I doubt you have a COP problem. I've had water in once (I ran this vehicle down about as low onm fuel as I could and then drained the last couple of gallons out and there was about 1/3 water in it) and as you suggested, it stumbled and ran poorly at all speeds.

 

[RIDE THE]

1st.. Stock or not, I would not do a kickdown blast in your truck in cold temps. I've seen trucks toss a rod with less than 100 miles on the odometer. Colder air temps means a more dense air charge (more boost).

Any dealer can access Mode 6 data in the PCM and tell you if any missfire counts have been stored. They don't even need to pop the hood. It's all done through the DLC connector. Go to a dealer an shoulder tap a tech walking through the parking lot and toss him $20 to check the Mode 6 data for you. That will tell you every recorded misfire since the last PCM reflash.

 

[emig5m]

Any dealer can access Mode 6 data in the PCM and tell you if any missfire counts have been stored. They don't even need to pop the hood. It's all done through the DLC connector. Go to a dealer an shoulder tap a tech walking through the parking lot and toss him $20 to check the Mode 6 data for you. That will tell you every recorded misfire since the last PCM reflash.

Yea... As I said, already had it to a Ford dealer and had them run a complete diagnostics check and they said they found no problems. I'm starting to think that it might not actually be the motor but perhaps the tranny? What would be the symptoms of a bad Transmission Range Sensor? But then it's back to the point of why it doesn't do it when it's warm outside (reason why I forgot about it all last summer) and only after falling below 60f (I previously thought it was around 50f but it's actually around 60f when the problem starts showing up).

So the outside temp pretty much would eliminate everything including water in the gas? What if some plugs are going bad and the added boost from the cooler and denser air is momentarily blowing out a bad/weak plug or two for a couple seconds? The crux of the problem solving is being that the problem shows up when the outside temp drops below 60f and no codes are showing in the system....

Hey when I get some time, would it help if I where to take a video from inside the cab while driving so you could see/hear what I see/hear?

 

[emig5m]

What about a MAP sensor or Barometric Air Pressure sensor? I was going to go take a video right now but my camcorders battery needs charging....

 

[emig5m]

Ok I just took some video but the outside temp was climbing over 50f so it's starting to fade out. Around freezing is when it does it really bad and for a longer duration. Here's the video, you can hear the brief stumble when I mash the gas and on the kickdown: Engine Stumble When Mashing Gas - YouTube Also note, it doesn't just do it on kickdowns (i.e. turning off OD) just seems to do it worse on kickdowns. Putting the vehicle into neutral at speed and mashing the gas it seems to rev up quickly and smoothly (but then there's no real load on the motor).

Maybe tomorrow early in the morning or later tonight when it drops to around freezing I'll take another video where it can get up to four times worse.

Also, I notice that there's some oil puddled up on top of the block. Looks like it might be the right head gasket? The left side of the block when standing in front of the vehicle looks dry.

^ Something to be concerned about or normal amount of oil for 64k miles? There are no drips underneath the vehicle on the ground and normally don't have to add oil between scheduled oil changes (3k miles).

 

[DMassey]

I bet your rear pcv line is blown out, and dripping oil onto your block. It is sucking in air and causing your stumble. The elbow on these pcv lines blows out all the time.

 

[emig5m]

I bet your rear pcv line is blown out, and dripping oil onto your block. It is sucking in air and causing your stumble. The elbow on these pcv lines blows out all the time.

Oh thanks. If that turns out to be the problem and resolves the issue, I'll Paypal you some money for the help. I'm really desperate to get my L back up into tip-top shape as I plan on keeping this vehicle for the long haul.

 

[emig5m]

Just to double check to make sure I'm going to be checking the correct PCV line, is this the one I highlighted in yellow here:

Can I get a part number or the actual part name for that so that I can see if I can find one in stock tomorrow (the elbow I assume is the part that goes bad and/or pops off). Also, I read that you have to pull the S/C and intake to get to it? I can't do that as it's too cold out and I don't have a garage and really only have a small amount of half-assed tools. Maybe it would be quicker to take the Sawzall and cut the entire intake off and just re-glue it back on with JB weld when I'm done?

 

[emig5m]

Ok, if I'm correct, old part number is...

F65Z-6762-BB

New part number is...

F65Z-6762-CA

This is for that elbow only. Someone correct me if I'm wrong.

And damned, there must be an easier way than removing the intake. What about removing the head unit (stereo) out of the dash and then cutting a hole through the firewall with a Sawzall?

 

[DMassey]

The hose you circled is not the pcv hose. You highlighted one of the intercooler lines. I know it sucks, but it is easier to get to that pcv hose with the blower removed. I'm sorry I do not know what the part # is.

 

[emig5m]

The hose you circled is not the pcv hose. You highlighted one of the intercooler lines. I know it sucks, but it is easier to get to that pcv hose with the blower removed. I'm sorry I do not know what the part # is.

Yea, I can reach those, I was just outside checking them out and couldn't make sense why they would be PCV lines if one goes to the bottom of the radiator and the other to the intercooler. Can someone circle or provide a diagram because I'm just not seeing it!? Only thing I can see back there is those two lines and there doesn't seem to be any oil leaking back there (dry looking) and I don't understand how it would be physically possible for oil to get from back there to on top of the block directly under the S/C. :shrug:

I'm starting to get the itch to trade it in on a brand new truck as I'm a person without patience and get frustrated easily and mechanic work is the thing I hate most, heh. I'm trying to remain patient and get help, but I've been dealing with this for two years and not even a Ford dealer could diagnose the problem and the Lightning forums are so ever dead anymore.