Idle and accelerating

Hi Rcalver1,

Do you have any codes?

I suspect that the PCM is getting some incorrect info from one of the input sensors it uses to determine correct air/fuel ratio. Keep in mind, the PCM needs to know how much air is coming in so that it knows about how much fuel to add to achieve this correct ratio.

When you start the engine and it is cold it is in open loop and not looking at the sensors to determine what it needs. The PCM uses a preprogrammed set of numbers to determine best operation.

After it warms up and goes to closed loop it starts looking at the sensors and if one of these is incorrect it will start running poorly.

Here are a couple of guides that will walk you through the common causes:

https://www.2carpros.com/articles/engine-backfires-while-running

https://www.2carpros.com/articles/mass-air-flow-service

Start with any codes and that will hopefully point us to the culprit. If no codes, we can figure out the best course of action.

P0171 and P0174 are for Bank 1 lean. The P1131 and the 1151 is an o2 sensor says it is at the limit for the fuel trim which means it is indicating a lean misfire.

The P1451 is for the evap system.

The main causes of lean misfires are listed in this guide. If you have no vacuum leaks, have you checked the operation of the MAF sensor. Also, are there any leaks in the exhaust before the o2 sensors?

https://www.2carpros.com/articles/repair-lean-mixture-codes-p0171-or-p0174-on-some-manufacturers

https://www.2carpros.com/articles/mass-air-flow-service

If the engine runs well at first, and then it starts running poorly I am pretty sure you have a sensor issue.

Do you have a scan tool that can monitor the live data? We need to see what the MAF is doing when it starts to misfire.