I have an XSi 2.0 16V Phase 2

For info, I have already fixed or replaced the following:
Battery
ECU
Fuel Filter
Fuel Pump
Idle Control Valve
Spark Plugs
MAP sensor
Engine Management Temperature Sensor
Engine Mounts

Car has been ok for a bit but I have just noticed it starting to play up again.
It still has a rough idle and car shakes a little bit but and I'm still not sure how to sort this out.

This isn't my biggest problem though.
The main problem is a jerky feeling whenever I take my foot off the gas pedal.
Doesn't matter what speed or gear, it can happen whever I'm driving and about to slow down.

It only happens once in every 5 times but all I have to do is take my foot of the gas (without breaking) and the car will make a jerky movement instead of steadily slowing down.
If it occurs when I plan to step on the brakes immediately after coming off the gas, the car will really jerk.

Now the only thing I can think is that my garage didn't do my engine mounts properly. He charged

________________________________________

306 LX 1.4 Phase 2
**Current Body Mods**
4 x 4" Exhaust System
Full B/Kit (Front, Skirts, Mirrors & Rear)
Bonnet with Scoop
Full Tinted Rear Windows
17" Alloys
Lights

But car was fine for 2 weeks. In that time I changed the MAP sensor and Engine Management Sensor.
This means I had to get under the inlet manifold as the XSi's MAP sensor is in a dodgy place.
I thought maybe that could have something to do with it.

It's not been a sudden thing, it's happened over time.

________________________________________

306 LX 1.4 Phase 2
**Current Body Mods**
4 x 4" Exhaust System
Full B/Kit (Front, Skirts, Mirrors & Rear)
Bonnet with Scoop
Full Tinted Rear Windows
17" Alloys
Lights