Hi I have a 1997 cadillac eldorado 4.6l northstar engine. It went from normal to blows clouds of smoke out the rear exhaust. Run sluggish.

SOURCE: RICH

DTC (diagnostic trouble code) P0340 is indicating a fault has occured in the camshaft position sensor system of the cars' electronic engine control system. DTC P0717 is for a transmission input turbine shaft speed. Typically these codes are unrelated. Both the sensors are variable reluctance devices. They have no moving parts and as such are robust and not usually prone to failure. But they can and do fail. Are either codes "hard" faults or are they in the continous memory of the computer? Does the P0340 clear itself when the engine is shut off and restarted? Can you cause the P0340 to reoccure just by starting the engine and with out driving it and revving the engine to 1500 to 2000 rpm for 1 to 2 minutes while in Park? The P0717, when cleared should only reoccure when the car is driven. If the camshaft position sensor has been replaced and still the same code occures make sure you have the correct information as to the meaning of this code in regards to your particular model year and engine. Does the engine have a camshaft position sensor for each camshaft? If so what is the DTC code for the other camshaft position sensor. Yes, the engine's computer (ICM, PCM, ECM, all terms for same thing) could be faulty but in most cases this is not the problem. Does the transmission seem to shift properly? You probably won't notice a differnece in the way the engine runs if the camshaft position fails due to the default stratagy used in the ICM. Wiring would be my next area of concern. Does the wiring for the camshaft position sensor and the transmission sensor go through the same wiring harness and could you have a poor connection at some point in that harness? Inspect the wiring and the hardshell connectors throughout the harness. Let me know what you find out. Thanks

SOURCE: car won't start wants to turn over but nothing.

sounds like you have a blown head gasket this would explain loss of coolant and running poorly excessive smoke.

SOURCE: 1999 grand cherokee when iscan the vheicle dtc code is p0441 So i checkED purge solonoid and leak detection pump and gas caP AND CHANGE ALL NEW. AFTER 3 OR4 DAYS IT COME BACK. wHAT SHOULD I DO?

smoke test for leaks.

SOURCE: 1997 cadillac eldorado running hot

Sometimes a vacuume leak can cause overheating problems too.

SOURCE: 1994 Lexus ES300 large cloud of smoke.

Valve stem seals can cause this problem, but normally only when first started. Oil in the rocker cover seaps through the oil seals into the cylinders and is burnt up on start up.
Try a "STOP A LEAK" additive and it may reduce the oil consumption and smoke.
I found some on e-bay and it worked on my tired old escort. It even stopped the rattling tappets.