It doesn't take much fuel in the valley to put an overwhelming stench in the truck, particularly when the valley warms it up and the fan pushes it back at the cab. As for the black smoke and lack of power, perhaps the two are related. Black smoke is typical of too much fuel for the available air. If your boost numbers are low, you won't be making as much power and milage will drop. Whats the condition of the air filter? There are also several spots on both the exhaust and intake sides that can be leaking, affecting boost levels. If it's on the exhaust side it can put a diesel fume smell in the truck too. The ehaust side has the manifold to the block, the manifold to the up-pipes, the up pipes to the collecter, the collecter to the turbo, and then the turbo to the downpipe. The up pipes to collecter joints are difficult to see but have a dougnut type gasket in them which can go out or simply loosen. You will see some soot around them if they are leaking. Oddly enough, an exhaust doughnut from a SB chevy will fit. On the intake side there are of course all the boots that need inspected. You cannot check them by feeling at idle since you're not building any boost at idle, and I don't recommend trying it while driving 60mph down the road. The turbo itself can receive damage and not give you sufficient boost too. There's also the wastegate on the turbo, which needs to stay closed normally.
99.5 PS CC 4x4 SRW ZF-6
Triple Pillar Gauges; Fuel pres, Pyro, Boost
AE, Alldatadiy, and half a clue
- AKA "The Big White Truck"
It's not so much WHAT you say, but HOW you say it that causes problems