silverslug96

pardon my lauguge but I don't know what to do.

Problem...it surges/bumps/stutters....only when I'm already moving (not from a stop) and the transmission shift into a lower gear causing the rpm to go below 1,500. Once I'm rolling and RPM's are low, if I push the accelerator causing a demand (or load) the truck surges. It will only do this at LOW rpm because once is down shifts causing the rpm's to go above 2,000 the surging goes away.

fuel mileage went from 17mpg to 13mpg

I purchase this 1996 f150 with the 351W with 179,500 miles on here. Since then I've put about 3,000 miles on here and replaced several things to include;

cap
rotor
wires
spark pluges copper (autolite) gapped at about .45
air bypass valve
ignition control module
pick up (located inside distributer)
O2 sensors (both banks)
and...fuel filter

I've checked timing and adjusted from 10-14 back to 12 btdc and problem is still there

I've cleaned the throttle body and used seafoam in the tanks and Vacuum lines (the amount of white smoke always surprizes me)....

THis is a completely stock truck...no mods

thanks,
Damon

qdeezie

I'm not a 351W owner so I don't know the gap specs off hand, but that .35 gap looks very small. The 302s range anywhere from .042 to .046 on certain years and I think .052 to .056 on other years. My gap is at .055.

Wondertwin1

The 351w gap is supposed to be .042-.046. Mine are gapped at .053. Also, try changing your fuel filter.

silverslug96

thanks for the quick reply

type-0
my spark plugs are gap to .45 (not .35)

and, I replace my fuel pump about 500 miles ago thinking that was the problem

I've noticed, it seems (surges) to be worse when my truck is at it's hottest. It's been around 100 degrees the last two weeks. But the trucks been doing this for about a month.

silverslug96

could it be my tranny or torque converter?

I change the filter and fluid with ford products...and check the level...it's on the mark!

BigGreyBox

When you adjusted the timing did you pull the spout plug? Could be the timing is off and its advancing wrong.

silverslug96

yup...

and I didn't loose it

silverslug96

today,

1. I double checked the whole ignition system. Rotor to spark plugs

1a. while plugs were removed, checked compression; lowest was 163....highest was 175 (not bad for 181,000 miles)

2. removed egr- cleaned and inspected. passed

3. removed tps sensor- checked with multimeter...change in resistance looked smooth though out the entire range.

4. replace a couple of vacuum fittings.

5. fresh gas in booth tanks...

will update after a couple of days.

Ohhh....and installed a 2" leveling springs from rough country

Good old Bill

I don't think your 2" springs caused your problem, nor do I think your torque converter is the issue. Keep after the basic engine issue, by the way, is the check engine light speaking to you. Might want to run the codes and post them up.

silverslug96

I wasn't thinking the leveling kit is causing this problem... Just though it was a cool thing to say at the end.

As far as the (CEL); it's not on, and I've tried to read codes twice (OBD2) and I get nothing. There was about a two week gap between each attempt to read codes.

Thank you for the reply. Any more ideas are welcomed.