i have a 2000 blazer 4.3 vortec throwing codes p1345 and p0300 just had the tranny rebuilt since then been having issues with the engine.
the truck starts and idles fine but i try to rev it and the rpms wont go passed 1700 put it in gear and all it does its creep. replaced the wires plugs cap rotor distributor ignition coil and ignition control module but still no luck

 

Have you checked the fuel pressure?

 

Yes I have fuel pressure

 

How much do you have at idle? How about when you step on the gas?

 

about 900 and when i step on the gas it only goes up to 1700

 

Have you actually done a full fuel pressure/leakdown test?

Or did you just hit the Schrader valve to make sure fuel squirted out?

 

When the trans was replaced who did the R&R?
It's not uncommon to remove the distributor to get at the top two bellhousing bolts. If the distributor wasn't replaced in EXACTLY the same position you can get those 2 codes. Check the cam retard angle with a good scanner or Car Gauge Pro App. should be 0° +/- 2°.
Another possibility is they left it in when lowering the trans and cracked, bent or some other way damaged the distributor or cap, rotor, CMP sensor or a combination.
I'd take it back and demand they fix it.

 

Your distributor is not installed correctly. P1345 indicates that it is off at least a tooth. Did a quick search for you. Read the second post on this thread by Captain Hook: https://blazerforum.com/forum/2nd-ge...uestion-83333/

 

Very good explanation. One thing I didn't see mentioned was that the Cam Retard Angle must be set above 1000 rpms. Probably just missed it.
Car Gauge Pro app is an inexpensive app that when used with a cheap Elm 327 bluetooth adapter and your phone will read all the data just like an expensive scanner.
Including cam retard angle.

 

I meant to also echo olddeerslayer's second possibility that if they didn't remove the distributor, then it either got damaged during the tranny install or the power/signal/ground wires for the CMP got damaged. If you're not paying attention and you drop the rear of the engine too much the distro will mash up against the firewall. Either way, your problem lies with the distributor.