newbie with a question (like most do)

[rweba03]

hey guys i am having a few problems with my 99 f250 and since i have had a ton of good advice on similar forums for my boat i wanted to see what i would come up with here. for the past couple of months my mpg have been dropping like a rock it seems i went from 15-16 to 9 and that is killing the pocket book. i know that it is getting colder and at first i thought that it was the additives they put in the diesel here in idaho to help out but it has never dropped that low. as well when i go to start my truck i get a huge cloud of white smoke coming out every morning i am assuming that the two are related. then the other morning i went out to go to work and it would crank but never go all the way over it did it long enough to totally drain the battery. i am needing some advice on what to look for. i can hear the fuel pump running so i am pretty sure i am good there. the gloeplugs have me a bit worried if they have gone bad but other than that is there something else to look at??? this truck has been a totally sweet truck and i have really tried hard to keep everything in top shape but because things are pretty tight right now money wise i was wanting to exhaust all options before somebody took my money to tell me what i could have done myself so any advice would be greatly appreciated!!!

[95dieselsmoke]

Check out the GPR. Have you changed the fuel filter recently?

[rweba03]

no i haven't changed the filter in a bit i will try that. my local mechanic was suggesting that before i dig into the plugs i take a look at their controller first because it is easier and goes out a lot easier. i am pretty sure there is something wrong with the plugs because yesterday even when it was warmer (42) the truck had a hard time starting still. the fuel filter would be a good reason for the horrible gas mileage though. thanks for the suggestion.

[rweba03]

so after looking at the truck today the filter is a bit dirty but nothing that should drop me that much. i replaced the block heater (totally burnt out) and then took some amp readings on my plugs. on one side i got 2.4 and on the other i got 5.2 so i then went and took readings off of my dads truck (exact same truck) and he was around 13 for an amp reading on each side so in the near future i see about 4 hours changing some gloeplugs. i am still looking for any suggestions on what i can do for better gas mileage and then hoping that the new plugs will help out with the starting and cut down on all the white exhaust that i get every morning.

[95dieselsmoke]

Did you replace the grp? They fail very easily, if you insist on replacing the plugs I would also change the gpr at the same time if you havent already... or just replace the gpr first to see if that does the trick.

[rweba03]

my mechanic said that we could test it with a volt meter so we put a volt meter on the grp on it had power going through it so i would assume that it is working. you know what they say about assuming though. when i turn the truck on it feels like it is clicking in. i am an electrician but don't know much about truck wiring but the grp seems to me like it is a relay of sorts so that is how i treated it. am i wrong for assuming this??