location of the ecm

I was recently given this car by a friend and although it has done 158000 miles the car has the full service history and recently passed an MOT ok.
I have an intermittent slight hiccup or hesitation every now and then. I have fitted new spark plugs but this has made no difference. The car is really of little value (but invalueable to me) and I cannot afford to have it electonically diagnosed however I did phone the garage that have serviced the car and they suggested it may be the thermal sensor in the ECU.
What do you think and is this item easy to replace?

[quote:ff2a0f08f8="ham"]2000 jetta 2.0 engine
no cruise control
The local dealer scanned the car, and determined that the ecm was causing the intermitting miss. I do think this is correct, however the replacement ecm is about $1,400. I believe I have found one at a salvage yard. I need to match the serial # on my unit. Without completely disassembling the engine compartment (or dash)
Where is the ECM?[/quote:ff2a0f08f8] Lift your hood and it will be located under the enginge cowl which is at the base of your windshield you will have to remove your wipers and the cowl and it will be dead center. good luck