Hi All,

I have a 92, F150 supercab, 4.9L, Mazda 5 Spd Manual, 4x4, Flowmaster 40 with 3" pipes, K&N FIPK, hot aftermarket coil, accel wires, I don't recall the plugs, 3.55 differential, and 31" tires "bigfoot AT", rear adjustable air suspension, and tow package. I have replaced my: clutch/slave cylinder/power steering pump/oil pan gasket/radiator/water pump replaced/02 sensor. I have a fiberglass shell on the truck that fits it well and is flush with the roof. There are 156000 miles on the truck.

My question... my truck has never been a gutsy vehicle. I have never been able to start from 2nd with much force. This vehicle has never been the torquey 4.9 that I read about. I bought it used from the dealership at 89K miles. I recently started hauling about 500 pounds of stuff every now and again and it is even less powerful. It rides very smooth. I have never noticed it misfiring. The clutch is fine. I had the codes pulled yesterday and there was no codes listed. There are no vacuum leaks, this was tested the prior day. MPG is about 13 city and 15 highway at 75 mph and 16-17 at 65 mph.

I had a Ford tech replace the water pump/slave cylinder/oil pan gasket and he stated that the truck runs like every other 4.9/mazda trans 3.55 that he has seen. He didn't see the point in testing compression as it runs well. I am wondering if I am missing something or am I having torque envy. I was hoping to pull a couple of ATVs and trailer this deer/elk season, but I don't think it is up to the task. Any comments or ideas would be appreciated.

Thanks,

Manny

 

Well it's a 6 cylinder, and an old one at that. The tires didn't help the lack of power either.

 

for the exhaust- does it have just a muffler and tail pipes or is it 3" exhaust all the way and does it have a cat? 3" exhaust isnt exactly the best setup for a 6 cyl.
i'd do spark plugs if your not sure about them. and you should be getting better than 17mpg on the highway. you should be in the lower 20's. i was pulling off 22mpg going 65mph on flat land and just over 16 at 85mph on hilly land.

 

It ran the same even before any of the mods. The difference that was noticed was that I didn't need to down shift to 4th for a hill near my home.

There is a cat, then 3 " pipe then muffler then 3" to a y split exhausting to 2 2 1/4" pipes. The tires really didn't seem to effect the system. The best it ever had was 18 on the highway. This was the result of reading performance threads several years ago... high flow intake high flow output... i.e. let it breathe.

It is a six. I'm wondering it if it just a six, but so many others state that the six is a stronger puller etc...

 

It's a low revving 6, all torque and very little horsepower. It can pull anything, but you can't be in a hurry. I'd bet the Flowmaster and oversize pipe is hurting the low end torque though. You have the right gears for those tires.