I have the same year and model truck, my engine is a detroit, same thing almost..Sounds like the same problem i'm having with my century. Found it to be a code 39(EGR VALVE). Replaced the valve and still having problems, found a leak in the egr exhaust canister and it's now in the shop being replaced, hopefully this will fix the problem. My truck has 900,000 plus miles on it. I'm not expecting to get great power on the hills, but I would like to get better fuel mileage than 5.5 @ 65mph. Come to think of it my truck was blowing black smoke as i got down the road for about 1.5 and no one could figure out the problem. replaced the valve and it has stopped blowing smoke all the time just on shifts. Hoping thing will fix my system. although i've heard that this egr engine is terrible and the system may go out again.
But I would say have your shop check the egr system, I was told that it could be cleaned out and this may help your problem, if not it need replacing. Best thing to do is replace the whole system if you have the money, this way you know nothing is wrong with it.
|