If you are changing the distributer I suggest spending the money and put in an Accell distributer gear on your distributer. These gears are made of a harder metal than the stock (brass) gear, and you do not have to worry about it wearing out. The modification you heard about requires the engine to be removed. It is usually done during a rebuild, otherwise forget about it--it's not worth it.
The p1345 probably has to do with the timing being off. You are correct that it has to do with the cam sensor -- this code is common when the timing is off.
This will get you close to the right timing -- bring number 1 cylinder up to TDC on compression stroke. Take the distributer cap off -- the rotor should be pointing at the number 8 scribed on the base where the cap screws down to -- look close for the 8 because there is a 6 also scribed into the base but that is for a 6 cylinder. Adjust the distributer so the rotor is pointing at this 8.
This will get you close, but a trip to the dealer is a must. The code reader or scanner you need is called the GM TECH 2 or a Modis scanner. These scanners are not for the novis mechanic, they are for a dealer or a professional mechanic -- they cost around $8000.00. A trip to the dealer to get the timing right will cost around $40.00. But if you insist on timing it yourself then you have to invest in a GM TECH 2 scanner or a Modis scanner.
Wednesday, September 24th, 2008 AT 6:09 PM