I think my injectors are getting bad, if I add the injector cleaner/lubricator it makes engine run like normal. It is an Isuzu FTR with the 7.8 litre engine. Have 320,000+ delivery miles on it. Have never had to add oil between oil changes at 6500 miles. The problem I am having: If I accelerate too fast, or press the pedal too hard before engine is in upper rev-range, engine will go "soft" for a second, loose some power and have an additional mild vibration. Shut it off and let sit a minute and it will go back to normal. Some times it like to roll black smoke. Shows no code on computer. I started using Lucas fuel treatment and the truck runs properly just about all the time. If the ratio gets weak the problem re-emergess. Increase the amount of conditioner and engine runs properly again.
Suppose to get a new truck after the first of the year, but I think my luck will runout first. Injectors are $650.00 each and 12 hours labor. Truck is only worth about $3000.00 the boss tells me. I am at a satalite wharehouse but at the main wharehouse they have started buying better quality fuel and adding additive and they believe it is worth the expense. Mostly run ND, MN and MT, yea it gets real cold at times.