Acceleration problem with 2004 FX140

[weatherman]

Simple problem and hopefully a simple solution. If I accelerate QUICKLY with my 2004 FX140, it will only reach 40mph. If I slowly increase the speed over 15-20 seconds or longer, it will get up to 55 mph every time. Any ideas on what the problem is? I have changed the plugs.

[Madfish]

Re: Acceleration problem with 2004 FX140

I would look at the air filter, make sure there is no oil on it. If there is oil on it, your engine oil level is too high. With cold engine, oil level on dipstick should be no more than 1/4 inch above low mark. With engine hot, you do not want oil level above full mark.

I would also check compression on all 4 cylinders. Make sure they are all within 5-10 lbs of each other.