Originally Posted by oldtrucker

My 1999 5.4L has just "developed" the same problem. I just logged in today looking for advice on how to proceed. My truck was running like a champ with 160K miles, and then I had a local shop do a fuel injector cleaning. Ever since then it has this slight stumbling when accelerating from stop, but pretty much only when it's cold. If you give it a little more gas it accelerates normally. When the engine is warm, that problem is not there. But, I notice that at 50 mph, if I let off the accelerator, the engine stumbles again, as if it needs more fuel. If you get back on the accelerator it picks right back up and runs normally. I took it back to the shop and they checked it out - no codes come up on their machine and everything seems to be connected properly. They suggest changing the plugs, which I have never done, but I don't think that fits the scenario. Any comments or suggestions?