I have an '02 Supercrew with 211K, had the truck for 5 years, bought it from my dad. The truck has had an exhaust leak on the passenger side for as long as I've owned it. In the last 2 months it seems to have little bottom end power, especially while driving around town. But here's the thing, doesn't do it all the time. Some days it runs fine, others after driving for a little while it really seems to lag between 1500-2000 rpm. Once it builds rpm it's not bad. Used to have enough power to spin the tires, now not even close. When it's acting up you can step on the brake and step on the gas and it will only rev to 1000 rpm.

I have a friend who has a shop, we've scanned it several times. First said it was running a little lean. He checked the fuel pressure and it was really weak and figured the cats were going. I changed the in tank pump, fuel filter, had the front cats knocked out and changed the rear cats. Always kept up on my regular services, flushed the tranny last fall, changed my plugs, I have a cold air intake on it.

Today I took it to Ford to see if they could find anything different. They said oil pressure sensor was sparatic. Changed that. Said they couldn't do anymore diagnostics until the exhaust leak was fixed and then gave me a quote.

I am just looking for any ideas or anyone who has experienced anything similar. I do love my truck and have a hard time justifying buying a new one for $50+ K. But I don't want this to continue being a money pit. PLEASE HELP!!!!

 

Clean the MAF sensor. Oiled air filters can foul it.

 

I've cleaned them many times with no different results

 

Might be a transmission problem or the 5.4 might just be worn out.