rough running 4.2L
rough running 4.2L
I have a 97 f150 4x4 . It has poor power of the line . It was not
always this bad. When I bought it I didn't notice it. It runs good
at high rpms. Two days ago the engine started to shutter. Worse
at idle and under load. If I keep rpms up it seems to run a little
better. I have changed plugs and wires. What else should I check?
always this bad. When I bought it I didn't notice it. It runs good
at high rpms. Two days ago the engine started to shutter. Worse
at idle and under load. If I keep rpms up it seems to run a little
better. I have changed plugs and wires. What else should I check?
Hi rough stock and welcome to FTE 
I think I'd check for a vacuum leak. You can take some Carb-Medic spray carb cleaner or something similar and spray it around the intake manifold, aiming at the vacuum hoses etc. If the idle changes when you spray it anywhere you've found a leak.

I think I'd check for a vacuum leak. You can take some Carb-Medic spray carb cleaner or something similar and spray it around the intake manifold, aiming at the vacuum hoses etc. If the idle changes when you spray it anywhere you've found a leak.
Any Engine Check lites?
Do follow Racerguy's advice and don't forget about the 2 under the throttle body air intake.
Fuel/air filters changed last? Plug leads seated on tightly at both ends. Open the hood with it ideling, in total darkness and see if there is any blue flames a'jumpin
Karl
Do follow Racerguy's advice and don't forget about the 2 under the throttle body air intake.
Fuel/air filters changed last? Plug leads seated on tightly at both ends. Open the hood with it ideling, in total darkness and see if there is any blue flames a'jumpin
Karl
I'd hate to be the bearer of bad news, however you may want to search this site for info on leaking intake manifold gaskets and the damage it will cause to the top end of your engine.........I have the luxury of owning the same truck with my Prod. date within days of them actually fixing the problem.So therefore I wait and pray.Good luck.



