Exhaust backfire and Missfire

@dakotasanders based on the symptoms you are describing as well as the P1345 code, this sounds like either a bad camshaft sensor or a bad timing settings. Since P1345 relates to the camshaft and crankshaft sensors alignment to each other, you can't count out the crankshaft sensor either. I'd replace the sensors, reset the PCM. This from a workshop manual

DTC P1345 - CRANKSHAFT/CAMSHAFT POSITION SENSOR CORRELATION

Circuit Description

DTC determines if distributor is installed incorrectly, or if a mechanical malfunction is present in engine.

DTC will set when engine is running, cam sensor reference pulse is not detected at correct relative position with crank pulse.

Diagnostic Procedures

1. Perform POWERTRAIN ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK , then go to next step.

2. Install scan tool. Start engine. Using scan tool, monitor engine RPM. If engine RPM fluctuates up to twice the expected RPM, go to next step. If engine RPM does not fluctuate up to twice the expected RPM, go to step 4).

3. Replace crankshaft position sensor. After replacing sensor, go to step 8).

4. Check for proper installation of distributor. If a problem is found, go to step 7). If no problem is found, go to next step.

5. Check for proper installation of distributor. If a problem is found, go to next step. If no problem is found, go to step 8).

6. Repair as necessary. After repairs, go to next step.

7. Replace distributor. After replacing distributor, go to next step.

8. Using scan tool, select DTC, CLEAR INFO. Start and warm engine to normal operating temperature.

Select DTC, SPECIFIC, then enter this DTC. Operate vehicle within the conditions for setting this DTC.

If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, repeat step 2).

9. Using scan tool, select CAPTURE INFO, REVIEW INFO. If any undiagnosed DTCs are displayed, go to applicable DTC test.