jerking motion of a the 5.0

[forrealb50]

Hey, when i am driving down the street and my foot is still on the accelerator my car will jerk back and fourth. what happens is say i am at a normal rpm rate of 2.5 suddenly the rotation speed will drop to a 2.0 or so and then increase back to the original rate. this causes my car to jerk back and fourth as if i don't know how to drive stick. at first i thougth maybe my spark plugs have gone bad but after replacing them the problem is still there. i have had a mechanic check my fuel pump and that was alright too. is tehre anything else i should look any advice would be much apprecaited.

 

[forrealb50]

that is my friend posting with my name because he couldn't register. i hope someone can help him out...

 

[jerry beach]

This is normally called bucking, like a horse trying to throw you off. Pull the codes and see what the puter says is wrong. What year is it and what are the mods? People fix it by rotating the MAF sensor and various other means. Does it do this every time you try to cruise at a level speed, or is it rpm specific? If you dont know how to pull codes, I suggest you spend your $ on a Haynes manual, instead of a code scanner. They are not the best by far, but cover basic things like this.

 

[HISSIN50]

try pullin codes. what happened should have prompted a code to be tossed, even if the CEL does not come on. likely an electrical issue, like a PIP, but that is a wild hair toss out. get codes and go from there.
good luck.

 

[Tillman86]

Hey man I had a similar problem with my 86 check your spark plug wires for crossfire you may have to add some quality wires and separaters. I done this and the problem went away. Just remember you can't put cheap wires on them ponies...

 

[jrichker]

Dump the codes and see what the computer says is wrong…

Here's the link to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great.

See http://www.troublecodes.net/Ford/
OR
See http://www.dalidesign.com/hbook/eectest.html for more descriptive help
OR
See http://www.mustangworks.com/articles/electronics/eec-iv_codes.html