Hey, new member here. Looking for a cheap truck, and a neighbour is selling a 98 F150 with the 4.2. I can get it for $1000 certified/etested. I know I'm getting a beater for $1000, but I just want to make sure it won't be a $1000 paperweight right after I buy it. It does have 266,000km on it.

It seems to have a really rough idle. I read through a bunch of the other threads on here and most seem to mention that it stalls. This truck never stalls, it just runs rough. I'm sure it has an exhaust leak, and its got a pretty good ticking sound too.

What could be causing the roughness? Vacuum leak? If so, where are the most common problem spots on this engine?

He just did the plugs and wires, and hes got a new coilpack that hasn't been installed.

Any advice would be appreciated! Thanks.

 

on trucks as old as this, as is mine, the lower intake manifold is leaking, needs replaced.

 

This has been the only problem I have not found an answer for online. Went to a dealership and it seems fine now. Part #f65z*6762*ca T25 elbow.I live in Canada so yours may be different. The service Lady told me it was on the back of the engine, I'm assuming it is a crossover from tappet covers. Hope this helps others, I've owned this truck since 2002, and it is by far the best vehicle I've ever owned. Only $240.00 fix at a dealership.