Hey Guys,I Have a 1997 f150 with the 4.2 v6. It's drives fine when you're not hard on it, but if you need to go it has a hard time reving. It usually has to shift all the way down to first. Can't get it to rev well in second even when accelerating from a stop. Here's what I had done in relation to this issue. I did a complete tune-up on the engine. New oil, oil filter, new plugs, new wires, new coil pack. Also put in a new air intake, air filter, and MAF sensor. About a month ago I tore it down the intake cleaned it and put new clips on the IMRC linkages. I also tested the actuators for leaks and found them to hold vacuum well. Put it back together with new gaskets and also put in new fuel injectors. I cleaned the throttle body and replaced the 02 sensors. I also had my mechanic replace the fuel filter and fuel pump. I am kinda lost any advice would be great! Suspecting a cam position sensor?

 

Mine was having a similar issue, it was the TPS (Throttle Position Sensor), but there was a check engine code for it as well. It is a 30 or 40 dollar part from Oriellys. Not sure if it's your problem but may be worth a look. Also I'm 4.6l not 4.2 but I am sure there are similarities between the two.

 

Hey man,
​​​​​​ Thanks for responding. It ended up being the MAF sensor. I had put a new one on this spring, but evidently it was bad electronically. BTW, I did try the tps, and it made the throttle a bit sharper, but really what I am experiencing is a huge power lag. Can't get it to rev over 3000 unless you're in 1st, you can get 3500rpms maybe. Can't keep up to speed on a hill unless it's 35. Better not try to pass anyone. LoL 😆 From some tests I did it looks like some my cats are melted. But my timing chain is going so I am going to address that first. My mechanic thinks that with my timing being so sloppy that it's probably the reason for that lag. He said I probably should fix that first, then if I am having an issue then look at my cats. Thanks again.

 

" what I am experiencing is a huge power lag. Can't get it to rev over 3000 unless you're in 1st, you can get 3500rpms maybe. Can't keep up to speed on a hill unless it's 35. "
pretty much what my symptoms were but it ended up being tps lol. Guess I was lucky and got a cheaper fix.