Truck in sig is surging from about 1500 and on with load. Yesterday pulling gooseneck with truck on it, going up hill at 65 it started to surge in sixth running at 2000rpms. The more I concentrate on it, the more I noticed it. Just replaced the fuel and lift pump. Fuel pressure is at about 18psi. WOT can drop to 11psi. It is more noticable with the comp on. I had it on 5x5 and then went to 3x5 and still noticed it. Even accelerating and shifting gears from 4th or so and up, it seams that the more fuel I give it, the more it wants to surge or jerk. Of course that makes the pedal go up and down which I just push in the clutch and git er back under control. Any help on this would be great. I will run it tomorrow to see if I notice it with no load on it at all. Thanks everyone for the help.

 

have you checked the codes via the key method?? kinda sounds like an APPS problem to me. When mine went south, the truck would buck and jump in every gear unless I had the cruise on.

 

Drove it today empty, and it will do the same empty, but not as bad as I dont have a load. I will check the codes.

 

It sounds electrical. Check all your grounds on batteries,block,etc. Check wires coming from the alternator & make sure they are tight. One of them runs over to the TPS(APPS) sensor. Do the APPS reset. If you don't solve it with any of the above tricks, go put it on a computer & check the codes.

 

I had some surging at WOT last week. I bump started the LP and opened the fuel filter drain to check the fuel(kinda orange but no water) then wiggled the pump wire in case the scotchlock connection is going bad. The motor quit surging. I'm guessing a pump wire solder job is in my future.

 

pulled the codes last night and got 1693 with a 0500. Speedometer not getting a signal is the code. My speedo is working fine. I will check on the apps reset. Dont know where or how to do it, but I will do a search unless someone has better info. Dont know what to do about the 0500 code. Any suggestions?

 

After changing my batteries I forgot the do the APPS calibrate and my truck would cyclicly surge on the highway. You really couldn't feel it so much as hear it -- sounded almost like phase drift on a twin engine boat or plane. Calibrating the apps fixed it. I had no codes.

 

There is a thread on here that links to a DTT forum and has the APPS calabration. Easy to do and will at least help get the idle in the right place. Mine was .043 volts off. That is on a high of 3.5 volts and a low of .57 volts. I had a pretty good amount of travel off idle to bring the RPM up. That is gone now. For a 30 min. job it is well worth it. Have not driven it yet but will in a few minutes.

Randy

 

I replied to that thread as well as someone sent me to that thread. Not sure if that is the problem or not. Why do I have a 0500 code if my speedo works. I have a true speed on it, but the speedo works fine.

 

my truck is doing this in 5th and 6th. should i try the apps reset?

 

I you do it is one less thing to worry about. I just got back from driving it and It now has full throttle too. It seems to have helped my surge a some as well. Mine is not loaded. Mine is low boost, lower throttle. One thing you can look at is when you do the reset (per DTT, not just disconnectiong the batt's) you can move the apps sensor through the it full range and make sure the voltage goes up smothly and consistantly. If there are some places that jump around as you go through the travel that could be your issue.

One thing the DTT direction does not specify is you have to pierce the wire (for the APPS by the PCM, NOT YOUR VP WIRE) and leave the connector plugged in. For a 30 min. job it is well worth it.

Randy.

 

sometimes the 0500 is caused by wheel spin... I set an 0500 on an icy road last winter. Never affected my truck and it cleared itself...

 

that may be it as the roads are icy. I will reset tonite and recheck. I will reset the apps tonite as well. Well, maybe when I get back. I have to pack.