I just bought a 2005 F-150 STX with a 4.2 v6. What common problems should I be aware of? Is the 4.2 a problem to change spark plugs on? I see the manual recommends a synthetic blend 5w20 oil. Do most owners use a synthetic blend?

 

The only engine with spark plug problems was the 5.4L v8. Use what oil that is recommended from Ford. The synthetic blend is what I have always used.

 

Thanks for the info. I am relieved to know I don't have the engine with the spark plug problems.

 

Any oil that meets SN GF-5 in 5w20 will meet the ford spec. If you want to use the motorcraft it is a good oil but any major brand will be just fine as well.

 

I have an 05 F150 with a 4.2. Right now it has 174,000 miles. So far I've put 20,000 in a years time and not a single issue. I use motorcraft 5W20 synthetic blend, I change the oil and filter every 5,000 miles and the air filter every 10,000 miles.

The plugs are on the side of the engine instead of on top like the 4.6 and 5.4. the early 4.2s from 97 to 98 would hydro lock. That issue has been since resolved. My 05 has plenty of power, it gets used for work, pulling smaller trailers and loads of tools and materials. My mileage with a mix of city and highway runs from 14.8 to 19 MPG. Pulling a popup camper out of Jackson Wyoming and down the Wind River Canyon I got 21 MPG.

My pickup is an Xl with roll up windows and manual locks. The vinyl seats, this is exactly what I was looking for.