its in the high 80s here, I can start my truck on second try. after it starts and runs for a few minutes I can kill it and crank it right back up but after it sits for a few it will only start on second try. ive put a new lift pump in and glow plug controller. only one glow plug is bad. what can this be?

 

first you need all 8 glow plugs or they don't do much good, I would bet that your due for a set of injectors and a new ip. it sound like you have injectors bleeding down or sticking.

 

the glow controller can fail to a four second only heat cycle , each time you turn the key on and off, open the door and watch the dome lite, see how long it stays dim, this is your heat cycle, if the controller see's to many dead gps it can do this to allso, check gp's and pay attention to time that the controller heats, to be certain it is not a glow plug problem, plug in block heater over night, and crank without, waiting for glows to heat, if it starts right up, it is a glow plug controller or gp's are bad, or bad connection some where in the high current system, the WTS lite is not a indicator of glow time frame. use only ZD9 plugs.