I recently got ahold of a 2001 F-150 with the 4.2L and 116k miles. This truck has been sitting for about 15 months now. When i went to start it it started fine and idled great. However, under load (or heavy acceleration) the engine hesitates. There are no codes stored and i just added fuel stabilizer and changed the plugs and wires. After doing this, it still hesitates.

Any ideas on what i should check next? Thanks for all the help.

 

Anyone have any suggestions?

 

I would also change the fuel filter and inspect the vacuum lines.
Val

 

Change the air filter and clean the MAF. Good luck!

 

cleaning the maf isnt a bad idea as it can cause all kinds of driveability problems, however i believe you ar experiencing wires or a coil breaking down,more specifically the wires. i have seen it multiple times, especially on the 3.8/4.2

 

Thanks for the suggestions. I have replaced the wires and plugs and the problem still continues, but that doesn't rule out a bad coil or distributor. I am going to check the quality of spark sometime with a friend.

Am i thinking correct MAF = mass air flow sensor? Any tips or suggesstions on cleaning this, or just remove, clean with a cleaner, and re install.

Thanks again.

 

you havent by chance heard a weird squeak from under the hood have you? the cam synchronizer sometimes makes noise when failing. this and the cam sensor are both known problems

 

Yes, that is the correct assumption. There are cleaners made for electronic sensors available at your local auto parts store. Just be careful to not touch the sensor wire as it is a very fine wire and delicate. It can easily be destroyed.

By the way what brand wires and spark plugs did you install? Good luck!