lag problem

[88stang]

i new to mustang forums but this seems like a good one, i have an 88 5.0 lx aod, when i put the pedal to the floor it goes fine until 3000-4000 rpm's, it lags i guess u could say, i dont know what the problem is, i thought it was starving for fuel or something but i ran some fuel system cleaners and it still does it, i replaced fuel pump and it still does it so i dont think its starving for fuel, any suggestions?

[87hybrid]

I'll guess a timing issue.....

[88stang]

its not timing cuz i have a timing light and ive set it, and had a mechanic set it also

[quick5pnt0]

I had a similar problem and it turned out to be the coil breaking up at higher rpms. Unfortunately though it could be a number of things. Have you tried checking for computer codes? That might lead you in the right direction, at least its worth a try.

[88stang]

i havent tried checking computer codes, how would i go about checking those? i never had to check them before

[quick5pnt0]

The easiest thing to do is goto autozone and have them hook up their scanner to check them. Otherwise you can follow the directions at the link below on how to do it yourself without a scanner.

http://www.muscularmustangs.com/test1.php

[88stang]

are u sure they can hook up a scanner on an '88? i had a friend ask them about that before

[quick5pnt0]

Yep they make and sell little handheld scanners for these cars.

[88stang]

oh awesome, thank you very much!

[88stang]

alright i got the scanner and it came up with code 34 EVP - (R) EGR did not respond properly during test -
EVR - (O, R, M) EVP sensor is/was high -
PFE - (O, R, M) PFE sensor is/was out of range - any idea's on what to replace first?