I replaced the PCV valve of my Toyota Vitz 2007 some time back, due to oil level reducing. After I got the car back from the mechanic, it had this weird behavior of making a sudden jerk after five or six seconds when car is stopped in traffic. Also, it jerked when shifted to drive gear from parking gear. Jerk is not that violent and it does not make the stopped car actually move forward. Its like the car is trying to jump forward.
After about a week or so, this got automatically fixed.
I repaired the car again from the same mechanic, this time a soldering job of an electrical cable which supplies power to one of the spark plugs. After I got the car back, it showed similar jerking behavior. Now its been three or four days and jerking has got resolved to some extent, but still car does not feel the same as it previously was.
(About the soldering job, two wires which supplied power to a spark coil had been damaged at the point the wires connect to the socket at spark coil. Mechanic told me that its hard to find spare sockets so he soldered the wires. But I don't think the cause of jerking is related to this, because the same behavior occurred previously too, when there was nothing wrong with the wires)
I asked the mechanic whether he did anything else other than soldering the cables, but he said no. But, he should have disconnected the battery, because the time in the dashboard clock was incorrect when I got the car back.
Few more information:
- My car had been idling roughly for some time now.
- Earlier the gas mileage was about 12.5km/l. But from few months back, it has droped to about 10km/l.
- After the repair, when the car is at a stop, it does not properly go forward when I release the break (without stepping on the gas paddle).
What could be the reason for this jerking behavior?
