Surging

[cbhawks]

1996 F-350 Automatic with Banks Power Pack and Transcommand Module. At about 40-45 mph the engine sounds like you are feathering the throttle. If you accelerate it's smooth and pulls fine. This only happens on level ground light pedal. I have set the cruise to eliminate my use of the pedal and the surging sound remains the same. Occassionally when idling you feel an engine vibration. Any ideas?

[fordnut85]

Any codes or anything?? Sounds like possibly a injector going south on ya but it is hard to tell without running an injector buzz test or cyl contribution test.

[cbhawks]

I'm new to this. Is there a way to check codes without taking it to the dealership? You also mentioned a buzz test. What is that?

[djsdiesel]

is there any noise to go along with the surging? Could be the EBPV activating at cruise. If it is cold enough for it to come on. Does it go away after it warms up?

[cbhawks]

No noise. Doesn't seem to matter whether it's cold or hot.

[fordnut85]

Most Autozones will pull codes for ya but make sure to get the code number and disreguard whatever they try to tell you is wrong with it lol. Post back here with any codes that were stored and we can go from there

Injector buzz test is done with a diagnostic tool, with the motor off it will actuate each injector individually making a distinctive "buzz" sound as you go through all the cyl, you have to listen for one that don't sound like the others.

Cylinder contribution is also done with a diagnostic tool, it tells you how much each cylinder is contributing to the total power output of the motor, helps to nail down which cylinder your problem is coming from.

Hope this helps.

[pipelayerjdh]

Mine used to do that with the SCT, before I upgraded the intake. I think it was dumping more fuel off idle than the engine had air to compensate. After the intake, it smoothed out and I could floor it with no surge. It could still be a injector issue, though.

[Stroked95]

My guess is the CPS, have you changed it?? The cps is the cam position sensor, I've read that your surging description might be a sign that its goin. Good luck

[cbhawks]

I haven't changed the cam position sensor. Truck has 106,000 miles. It has stopped running twice for no appararant reason, but that was several months ago. The truck restarted with no problems.

[Stroked95]

Yeah I would investigate the CPS a little see if that cures it. Swap it out with a known good one to see if it solves the surge feeling, hopefully a buddy lives nearby so you can try it out. Or ebay it I think they go for 50-90 bucks. Good luck