When I was driving around and after the light turned green (I waited for the car in front of me to go through first), I pressed the accelerator lightly and when I did that, the van was jerking/vibrating. It's been doing this for a long time and I have a P0449 for a bad EVAP Vent Solenoid (confirmed the issue with the Tech2Win software on my laptop), but nothing for the transmission unless the ABS light turns on (another story because of a faulty wiring harness). There is fluid in the transmission and it's not dark, plus no metal shavings in it and the van has about 160,000 miles on it currently. What can cause a jerky/vibrating acceleration after coming to a stop? The only engine code I get is P0449 for an open loop on the EVAP Vent Solenoid and no misfiring. It has an exhaust leak that got patched, but decided to open itself again. Engine air filter will be checked next, but I need to know what can cause this issue. Even the repair shops are puzzled.

 

if you accelerate hard is the vibration gone? torque convertor shudder is one possibility.

 

This issue occurs once in a while when driving and not every single time. The torque converter is the one that goes between the flywheel and transmission, right?

 

flexplate is used on an automatic trans. tc bolts to the flexplate, flexplate bolts to the engine. the tc has a internal friction disc that locks up and allows the turbine and impeller to spin with no slip. it pulse width modulates during initial lock up and can shudder. there maybe a updated programming flash to address this concern. Only the dealer would know.