I have had my 2005 Dodge Sprinter, 2500, with 214,000 miles, for one month. When I bought it the seller told me that after I drove it for a while it would become sluggish and not keep up to 70MPH. I have found that when this happens it may slow down to 50MPH going up a hill and takes a while to get back up to 65+ on the flat. Sometimes it goes into slug mode when I cannot accelerate normally in heavy city traffic. Slug mode happens at all speeds. When it happens I can get back to peppy mode by shifting into neutral, turning the engine off, coasting and turning the engine on. I tried this because I noticed when I stopped to go in a store and shut the engine off, it was peppy even if if the stop is only a few minutes.
Any help in killing the slug will be greatly appreciated.
crp
What do you know about the truck’s maintenance history?
If the answer is “nothing”, then–unfortunately–you have to assume that none of the required maintenance has ever been done, and you will need to have the scheduled maintenance for 180,000 miles performed. After maintenance, it will be much easier to diagnose any remaining drivability issues.
I am assuming that you would have mentioned if the Check Engine Light was lit up, but I will ask anyway.
Is the CEL lit up?
If so, is it on steadily, or is it blinking?
Classic sign of a clogged fuel filter on a diesel. Change the filter and if it doesn’t fix it, you have done some maintenance. If the filter is mounted to allow it, prefill the new one with fuel and have a can of starting fluid on hand.
Any chance the converter is getting clogged and pressure is building up? Slowing down, cutting the engine off, etc basically eases the pressure only to have it resurface once up to speed again.
Any oil consumption issues?