The weirdest thing is happening to me and I thought maybe you F-150 gurus could help (At least I hope)

Recently, I noticed that when I'm cruising along in a high gear and at low revs if I try to accelerate at a moderate to high level It will start accelerating for a second and then produce one or more jerks. I've had it produce up to four "jerks" in one acceleration.

In my attempt to describe this "jerk" I would compare it to maybe two gears meshed together and then it'll miss a tooth and skip a couple and then grab again.

If I'm in my normal operating range for any given gear I could PUNCH the gas and it won't produce this problem. I've even tried really giving her speed and I haven't been able to reproduce it at a low gear. It only happens if I'm in like 4th gear going twenty-five -> 30 mph and give it gas. This would lead me to believe it's not my clutch. I thought maybe it might be a u-joint, but I've heard they make noice when they're worn.

Also, I'm very religious with my sched. maint. I recently changed the tranny fluid and put in Mercon V Valvoline ATF. I did this maybe a month before this started happening. I was going to change the diff. fluid, but in the manual it says it's a "lifetime" fill unless you go underwater or something.

Please let me know what you're thoughts are because I'm VERY confused

Thanks for your time and assistance......

 

Do you have any mods done to your truck? Ie gears/ tires? Manual tranny right? Clutch slippage can produse this symptom. If it has glazing it will slip and grab. But if it is doing this in 4th at 25mph it almost sounds normal. I will go out and try mine later.

JMC

 

Yep, I've got a manual tranny, and BFG 285's....Let me know how yours turns up, but this just recently started happening. I don't think it's a normal condition.

 

I tried mine in 4th at 25mph and it didn't do it. Try cleaning your MAF.

JMC

 

I tried it again in 5th today and nothing.

JMC

 

Thanks for the tests JMC! I really appreciate it, but I was wondering why you think the MAF is the problem. You think it's the engine and not the drive line that's causing the jerk.

If so, where exactly is the mass air flow sensor located?? How would I clean it?

Thanks!!!

 

If it was driveline related it would do it in every gear and at all speeds. The MAf is loacted in the Air filter housing. Check out http://www3.sympatico.ca/jmc.chartier/air1.html
The MAF has 2 wires that measure the incoming air. When they are dirty that can cause problems. If you need more help on locating the MAF let me know.

JMC

 

Few more MAFS pics if you need them :

Stolen from HapynZap's server :
https://www.f150online.com/galleries...2028-49703.jpg

From the K&N FIPK install directions ( crappy pic )
https://www.f150online.com/galleries...2028-48036.jpg

If you follow the directions either from JMC or for changing the air filter, this would get you to the point of seeing the MAFS in the air cleaner housing.

Some take it out the remainder of the way, some clean it in place in the housing. My Misc ablumin teh gallery has the pics on how to get the MAFS out of the housing also, if JMC's doesn't do the trick first time ??

When you put it all back togehter, check all the hoses in the intake, to make sure one did not work loose, else the truck will idle rough, without settng a code straight away.

Steve

 

Steve,

'bout time you show up with some pictures.

Forgot to say what I use to clean it. I use windex with a Q tip. What do you use.

JMC

 

JMC

I took your advice in a post a while back and use the same thing, never tried anything else.

The cleaning does not seem to take any thing mroe then that.

I seem to recall some said they spray carb clearer in there or something doesn't sound good to me, but that is just me...?

BTW : If you need those pics for another post, they are in the Msic Album in my Gallery. I posted them local, so I did not have to go around to other servers any more

Steve

 

Thanks everyone!!! I'll try it first thing tonight!

 

Don't know if this is still a problem or not.

If so, try going to autozone and have them scan your computer.
P0608/P0609 are vehicle speed sensors(VSS) errors. The transmission doesn't know what gear to be in due to the malfunctioning sensor.

 

Yep, it's still a problem. I've been really busy lately and I haven't really been able to clean the MAF. Highmilage, the tranny is manual, could this still be the case then?

 

How many miles versus and when was the cluth last replaced, it could be getting old and losing some pressure and grab in high torque situations.

Brian

 

Ok everyone, sorry for the delay. I finally got around to cleaning the MAF. If I'm not mistaken, when you open the air filter housing the first sensor would be the MAF sensor. It looks like two little resistors with I think four wires coming out of it. If this is the MAF, then I cleaned it. Hopefully! I got a few Q-Tips and windex and went to work.

It didn't work. However, this problem, I've noticed, is extremely variable. I recently noticed it started doing it in ALL hard accelerations, not only low RPM situations.

I've even gotten into jams when trying to change lanes, etc.

But now, it almost completely went away. It's done it a few times, but nowhere near as much as it was lets say a week ago. This is TOOOO weird!

Let me know what your thoughts are....

I am completely convinced this is some sort of sensor problem not reading the correct air flow or fuel.

FYI: I've got a K&N Air Filter....Also, I regularly change my fuel filter approx. every 15,000-->20,000 miles.

I've got 53K miles total with no clutch replacement.