Just got home from a ten day trip in our motor home. About half way through began to belch exhaust smoke when heavy throttle was used at speed (like when going up a fairly steep grade). I have a boost gauge and EGT gauge and both indicated normal (6-8 lbs of boost and max of about 1100 degrees or less EGT) when the smoking would occur. As time went on the situation got worse.

Got home today and checked DTC (counting panel light flashes). Have a code 35, injector pulse width error - response time short. Also showed a code 78, waste gate solenoid fault, but I think this was left over from a problem I was having a few weeks ago with low or no boost which I was able to correct by snugging all vacuum and electrical connections and giving the solenoid a shot of WD-40 (per advice of John Kennedy).

Would appreciate any thoughts by those more expert about such matters before I place myself at the mercy of the local Chevy dealer.

Motor home, which I have owned since new in 1994, now has 248000 miles on it. The engine is a skirted block AMG new engine with about 70,000 miles. The injector pump was new with the engine which was installed by Peninsular.