Hello all! I'm new to the forums and hoping someone can help me. I have a 98 silverado z71 5.7 vortex with the code p1345 (camshaft/crankshaft sensor).. My truck is backfiring from the exhaust pretty bad, but it does not backfire when the truck is in park, but when i take it out of park it backfires like crazy especially when I'm driving and its also burning gas like crazy, and very strong smell of gas... I have recently changed plugs and wires, upper intake gasket, the lower intake gasket was done about a year ago... Any help would be greatly appreciated, thanks in advance.

 

It means your timing is way off if its backfiring and running that poorly. Check to make sure you put distributor back the way it was before, chances are you will need to take it to a shop to re time it.

 

Thanks fsxbob, ya I can tell the timing is definitely off, but did not know that would cause the backfiring... I appreciate your reply!

 

I am not sure I understand you. So you have camshaft position sensor error code, and you replaced what? Plugs, wires, gaskets? Why don't you replace the darn sensor? And reset your ECM?

 

Sorry, I did replace the cam/crankshaft sensor i just forgot to add it to the post... I replaced the spark plugs and wires and the upper intake manifold gasket all within the last 2 weeks... the upper intake gasket was bad and need to be replaced, but did not solve the problem and the code is still on. I've read somewhere that the cam/crank sensor can throw the timing off, and fsxbob above said that could cause the backfiring and loss of power... If anyone else could shed some light on the subject it would be greatly appreciated.

 

Check to make sure the cam/crank sensor is sitting correctly. Those sensor usually read a notch off a small wheel on the cam/crank and then fire at an appropriate interval after or before (engine timing). so if its not sitting in there properly the computer might have no idea what to do.

If someone who knows these motors better than I do wants to correct me please do, I am speaking from general experience

 

Will do fsx, appreciate your help sir! I was reading somewhere that 96-99 chevys you have to use the scan tool on the "cam retard" to adjust the timing & turning the distributor is not how you adjust the timing on 96-99 Models & "it will do nothing for the timing"... Please excuse my Ignorance on this... If anyone else can shed light on the timing it's greatly appreciated.

 

So did you get this fixed or what ended up happening?