Bmw z3


have read code p0340 replaced cam postion sensors cleared code .but the code has came

back.had car checked at bmw dealer but found nothing but 150.00 does fine at times but it misfires at start and the ck engine light comes on and the code is back.

How old is the car? If it is not under warranty, (if it was it should not have cost you anything), you should consider bringing it someplace other than the dealer. A local independent mechanic might be a better choice.

. Dealers are no better (or worse) than independent mechanics for almost anything you might need done on your car. They will almost always charge more per hour and often more for parts and supplies. They also tend to look at repairs a little different than the independent.

A dealer may well recommend work that strictly may not be needed, but could be connected to the problem or maybe replace a part when a little repair would fix it ALMOST as good a new.  

There is no need to bring your car to the dealer for any service other than service that is going to be paid for by a recall or original warrantee.  During the warranty period be sure to have all required (as listed in the owner's manual) maintenance done and to document all maintenance work.

I suggest that most people would be better off finding a good independent (Not working for a chain) mechanic. 

Note: Never ever use a quick oil change place. They are fast cheap and very very bad.

Misfire is not a sympton connected with a missing cam position signal. Are you getting a actual misfire code? Coil packs and the plugs themselves are often the source of Z3 misfires.

no misfire code the only code is the camshaft sensor.i used aftermarket sensors replaced left and right.the car runs fine about half the time and then it goes into
the no power mode will not even hardly pull out and the ck engine light comes on.
ck codes and the p0340 code is back.thanks.the car is a 2000 z3 2.8 i have owned it about a month.

Check your repair manual. You may see that there is a lug, or magnet, which passes by the camshaft position sensor (CPS) which the CPS senses and sends a signal to the engine computer. The path the moving part takes may be erratic (from looseness, warpage, etc.). Check that.
Also, check the wiring with a multimeter (voltage, ohms, signal), from the CPS to the engine computer.

thanks i will give it a try.

i have a 99 bmw 528i with the same issues, code p0340, i have replaced both cam sensors and also found the maf sensor to be broken, i replaced that as well, worked fine and then no power again. all sensors are from dealer. im running out of options. all sensors have the correct voltage or ohms. dont no what to do next

Did you not see the answer I posted to your question?