Jthomp

I have an 01 f150 4.2 L V6. Only had it a lil over a month now. Within a week of having it I was in a drive thru and the truck started shaking and cut off. I was able to get it cranked and coasted into a parking spot. Was told to change out fuel filter so we did. Problem went away for a day, started back shaking but wouldn't cut off. Place I bought it from said it needed a new fuel pump so I replaced that. Was fine for a few more days then the check engine light came on and started shaking again, code was reading spark plug 4 was misfiring. Out a whole tune up on it and was fine for a week. Not the problem is back and seems like it's getting worse. I may need to add that whenever it starts shaking while idling or jumping while driving, if I hit the a gas and rev up the engine the problem stops. I have no idea what's going on so I'm hoping to find someone that has had similar issues​and could give me some insight! Thanks in advance!!

the01kingranch

So it happens when you at a stop in drive it shakes and tries to die. Also while moving it does it also. But when you hit the throttle it fixes it? When moving and while sitting? Does it do it only at operating temps? Or when cold?

Jthomp

It doesn't matter if it's operating temps or cold, it'll still do it. And yes, anytime it starts shaking (acts like it's starving for gas or something) it clears out and is fine.

Aragorn

OK Time for 20 questions:
If you have a Tachometer is there a particular RPM range that this seems more common?
What is your idle RPM speed?
When they did this whole tune up did it include new coil packs or just plugs?
What kind of plugs did they put in?
Did they change the air filter?
How many miles are on the truck?
Does the jerking occur more frequently at slow speeds?
Have you checked the battery or had the battery checked?
Have you tried putting it in Neutral when it's shaking and has that made any difference? (obviously while not moving, don't try while moving)


I'm sure there are more questions that could be asked.

pmassey31545

No MIL codes when this happens?

Perhaps the MIL bulb is blown. Have you tried scanning it OR taking it to a shop for them to scan WHILE the problem is happening? I know we all like to work on our own vehicles, but chasing a gremlin can be expensive if you are not at least somewhat confident you have narrowed it down to a specific system.
EDIT: Nevermind. I actually re-READ the first post.

All that said...I have a 2002 with a 4.6L and it was skipping and such a while back. Acceleration was ok but under load or low idle it was rough. Turned out-as mentioned in a preceding post-to be the battery. Yep, the freaking battery. I changed coils, cleaned plugs, cleaned throttle body, changed air filter, changed the gas I was using, and so on. Finally pulled the battery to get tested and it had a bad cell (or 2). Put a new one in and BAM!!! Ran like a champ. So, worth a check.

Aragorn

I promised more questions so:

When they replaced the fuel pump did they do a pressure check and if so what's the pressure?
What's the weather like?
Have you looked at the IAC (Idle Air Control,) the MAF (Mass Airflow Sensor,) or the TPS (Throttle Position Sensor)?

pmassey31545

Add to that the EGR and throttle body.

Neophyte

so this is just me not being an expert. now that the problem is back is the light back on?
if it is what is the code saying? is it still saying misfire in the same cylinder? If so have you pulled that plug to see if it is still good?

thinking it could be a bad coil pack or it could be bad piston rings in that cylinder allowing oil into the chamber and fouling out the plug. I had a nissan that had bad valve seals that was causing plugs to go out constantly. with valve seals it smokes terribly at start up though.

djfllmn

iTrader: (1)

skinner? that you

FDHog

I have a jumper wire on my *** (gotta love the acronym) switch, and a few days ago, in the rain, it suddenly activated. Hasn't happened again, but it makes you wonder.