Using a OBD II scanner I got a P0456 and a P0440. My car recently was having bad readings with the gas meter so I had a crankshaft code and had the Crank Shaft Position Sensor replaced. That was great...until one day the car bucked and took out my solenoid, which in turn took out my PCM. Well, after replacing the two of those my car works again! Hallelujah! But, now whenever I exceed around 40mph and decelerate to about 25mph my car bucks. I was told a transmission flush would help that, so I did. I had the fluids replaced, and the filter. Still getting the bucking. I'm at a loss here. I don't know if those trouble codes have anything to do with it, but I'm worried the bucking will eventually wear out the solenoid once again. If anyone could please give me some insight on what to do next I would greatly appreciate it.

Edit: also even after having my crankshaft sensor replaced it seems I am still have inaccurate readings with my gas meter, must be attributed to the p0456 code..but I'm not mechanic.

 

http://www.obd-codes.com/p0440

http://www.obd-codes.com/p0456

 

I know the codes aren't causing this particular buck. IT can't be

 

When the car is decelerating with automatic transmission. Did you check the cable going to the transmission? They can stretch and the transmission may not know to downshift. May be a simple cable adjustment or it's sticking and needs some lube.
I'd work on finding the leak/clog in the evap system too. If you get vapor lock it can dick with engine performance.

 

Could it be an engine mount?

 

Then check the engine mounts... Best thing to do is deal wth the MIL codes if there are any performance issues.
If you have an ohm meter connect it to your thottle position sensor and move the throttle. check to see if the voltage is steady. Do a search on youtube. There are dozens of DIY tests for that