Friday night driving home from a football game I noticed the truck surging. I had the cruise control set at 70mph and it would speed up a few mph then drop back down to 70. Thought it was the cruise control so I turned it off and it still did it. Well this morning it done the same thing at 30mph. My check engine light has been on for several years due to me running over a fallen tree after hurricane Ike. It ripped off my vapor pump and I have never got around to replacing it. I went to check codes (key on,off three times) and it showed -------- for about 10 seconds then -done-. Did not show any codes. Does anyone have any idea what is causing this?

Thanks,
Robert

 

Id start by replacing the 30 dollar vapor can. After that see what you come up with, other than that id look to do a tune up. Rockauto.com has that pump for cheap

 

Agreed tune up. Definatly throttle body cleaning as well.

 

Robert,

Have the codes read by any auto parts store and post them up. Most places usually do it for free. If the check engine light has been on for a few years, it will not alert you to a new problem that just popped up since it has always been on.

 

He has already went through the steps to read codes and got nothing.
He is missing a vital piece of equipment on the truck, replacing that while resetting your PCM would prolly get you back on the right track.

 

Isn't the vapor pump and can just to filter the gas fumes out of the tank? It has been running this way for years so I don't think it is causing my issue. After reading on here sounds like the throttle body cleaning and EGR valve will be a good start.

 

Your right throttle body and EGR are a good place to start, but you are missing a part that will throw a code. Im not saying that the vapor can is the fix im just saying thats where i would start.
No matter how far you have gone with out it could eventually cause a problem, thats why i say start with the missing part.
Are you not getting worse MPGs?

Oh do the Key trick to find out your codes that will for sure tell you what your problem is, let us know what the code says

 

The parts are not missing there just not on right. When I hit the limb it pulled the vapor pump off breaking the plastic tabs. Well since they were both broken I figured I would try to jb weld it together. Well it didn’t work and threw the code for the pump and I also get the gas cap light on the odometer.

But now when I do the key on/off three times it says -------for a few seconds then says -done-. Don’t even get the vapor pump code anymore. I’m getting 14mpg around town and up to 21 driving 50 miles to work. So not getting too bad of gas mileage.

I removed the negative cable from battery to reset the CEL and it has not come back on yet but it's still doing the surging. I'm not conserned about the CEL being on for the vapor pump just want to figure out the surging. I figured out that it only does it when I slow down every so slightly. Or when I go down a little hill and it backs off the gas just a tad bit.

 

Sorry i misunderstood you when you said you "ripped" it off.
And forgot you had already done the key trick/
I would clean Tb check PVC, and a deep tune up

 

What does everyone change/clean on a tune up? I have 86k miles and have never done anything other then change oil.