At 130k miles, blew piston rod last December. Local mechanic put in a re-manufactured Jasper engine. 70 miles driven and it just does not run right.

Keeps throwing code P0300 - Random Multiple Cylinder Misfires.

Level road, easy driving, it feels fine. When you slowly accelerate or climb a small hill, the engine chugs like a standard that is in too high of a gear (1500 RPM @ 50 mph). If you press down on the gas pedal more, it goes into passing gear (2500 RPM) and the engine runs smoother. Also, about every 4 starts the engine misfires and violently stalls.

I thought it might be bad gas. It had been sitting since last December with 1/4 tank, I filled up with premium yesterday which diluted the old gas. Same symptoms this morning driving into work.

Please don't tell me to take it back to the mechanic. Out of 6 shops in town, he is the only one who would do an engine swap. He is as stumped as I am.

Thank you.

 

I know the plugs and wires are new, the gap was checked, Cam Position Sensor is new. The Jasper installation kit comes with a lot of new parts.

 

I hate to tell ya, but when a mechanic who can lay his hands on the vehicle can't diagnose it, you're just gonna get random guesses over the internet.

I guess the first logical question is has it been doing it since the engine swap or only recently???

 

Thank you Hammer,

It's been doing it since the engine was installed. 75 miles on the engine so far.