So last night i was driving home in the snow and i let the tires spin a little and the rear end seemed to be bouncing and as i was hitting the gas you could here a clunking/ knocking noise coming from the engine compartment in the brake booster area. And when i was backing in the drive way it was bouncing but no knocking because i was giving no gas. So i started it up this morning and pulled it out drove it for 10 minutes it still knocked when i stepped on it but the bouncing wasnt as bad there is still snow/ice on the road. My truck is a 04 f150 heritage xl 4.2 2wd. Please help!

 

Any chance you broke the left side engine mount? Transmission mount bad?

 

actually i just read my code and its engine 3 misfire so i will be troubleshooting that. Thank you

 

Misfires can seem like a knock sometimes. Is the P0303 the only code you had set?

 

No i had bank 1 and 2 lean conditions but ive had that for a few months i thought i fixed it. it was off for about 2 weeks then came back on a few days before the misfire

 

Check the intake bolts. I remember one of the threads talking about the intake leaking around #3, and that could be your P0171 and P0174 codes also. If they are loose enough, that could be part of your misfire code also. Post the pictures of the #3 plug when you get it out if you can.

 

Will do one other question if its code 171 and 174 is that usually the intake manifold gasket i dont know if maybe i got a faulty gasket or not but ive replaced both intake gaskets for the plenum and the isolator bolt but still get that code

 

Did you use Ford intake gaskets or some aftermarket brand? Just curious. Most say on the intake that the OEM Ford gaskets are better fitted than others. I'm not really a 4.2 person, so I don't have that much experience working on their intake systems. I'm more SB, FE, 385 and Modular motors oriented. I'll do the occasional V6 when necessary, but I'm partial to the V8's.

 

Pretty sure i used aftermarket the isolator bolts i used doorman

 

Just to let everyone know it is fixed replaced the spark plug and no more misfire also replaced fuel filter and no engine lean codes thanks for the help