I am having a HUGE problem with my 2001 3.8, I had it for almost 2 years and when I got her she was running great.

Earlier this year I put on flowmaster dual exhaust and some mac headers. After this mod, it really let out some hidden power in the vehicle! When I floored it from zero my rear tires would spin out of control, which did not happen before I did the exhaust.

A few months later what started out gradually became a substansial drop in power, and now my car struggles to get to 50 on the highway. I took my car to several "mechanics" that cant figure out what could be the problem with it.

The RPM cannot pass 2000-2500 while the car is moving, if I try to nail it to go faster all the car will do is hesitate more, the check engine light will blink, and inside the car builds up with some noxious fumes.

When I try and accelerate hard (when the transmission kicks down) I hear a rattling sound accompanied by the hesitation.....this led me to thinking that the transmission could be bad. After hundreds of dollars spent on a new transmission and torque converter, a full tune up, and even changing my fuel pump I am still having this problem.

I ran the car on the diagnostic computer and I get a code that says "intake air temperature sensor high input" and once again the "mechanic" doesnt seem to know why the intake temperature reading would be high, he simply suggests that I "change the unit". Before I spend myself into the poorhouse I really would like to know what is wrong with my vehicle.

ALSO my gas mileage is horrible right now! I am getting worse than I did with my '95 5.0 that had a ton of mods on it. I am getting about 10-11 mpg with combined street and highway (mostly highway) and I am always under 50 mph. I need help!!!!!!!

 

since the rpms are staying so low and hesitating i would suggest looking at your cats. if they are clogged it'll do that. and the rattle would be there too IMO thats what i would check. had the same problem on my jeep till the cats just simply blow up and put out all kinds of brown smoke and blew the cover off of them fun stuff. not really

 

go get ur cats checkd out.

 

Bingo. clogged cats and probably a broken piece logged in the pipe somewhere.

get it changed quick as it can really fry your engine by making it work too hard to get the exhaust out.

 

There is a little rectangular black box on the front of your intake right next to the EGR valve. It is known at Ford as a "DPFE Sensor". Spray yours out with some brake/electrical parts cleaner, allow to dry and then re-instal. See what happens. In the winter these go out very easy, especially if you are from a humid area and recently may have had a freeze. Moisture gets trapped in them with the carbon and when it freezes it expands and damages the unit, thus requiring it's replacement.

It's cheap to check and clean, and if it turnsout not to be the problem, then you're only out $5 for the cleaner and maybe 30 minutes time.

 

How did it turn out I'm kinda left wondering here...