DB9 Top Gear Track
AO Silver Member
Join Date: Jan 2007
Location: United Kingdom
County: East Sussex
The MAF sensor is nothing to do with the EGR
MAF - Mass Air-Flow, is at the front of the car and down low on the right (as you stand in front looking into the engine bay). It's down below the battery fixed to the side of the airbox, the other side goes off to the turbo. It senses the amount of air being sucked in the engine and passes this info to the ECU, the ECU uses this info to determine how much fuel is needed. They can be cleaned on some models, the sensor in mine (and I would expect on yours too) is a sealed unit and cannot be cleaned....never given me any trouble. They can have the electrical connector disconnected, it'll cause it to idle a bit rough but the ECU will use default settings, if the MAF is at fault it will run better.
EGR - Exhaust Gas Recirculation valve. In the drive for ever-lower emissions there is a pipe from the exhaust manifold to the EGR on the inlet manifold top, back, right of the engine. When you're pootling along the valve opens and allows exhaust gases and unburned fuel to re-enter the engine via the inlet manifold and, in theory, reduce emissions. They cause no end of problems as they stick open and cause loss of power. Lost count of the number of times I've had mine off to clean it.
MAP Sensor - Manifold Air Pressure sensor black box about the size of a box of matches, mounted on the inlet manifold just left of centre top, rear of engine. Does as the name suggests. Again, tends to get very dirty and requires cleaning from time to time. These have a relationship with the EGR as the manifold pressure changes when the valve opens.
How old is the car and how many miles has it done? When you suffer the loss of power do you get any warning lights flash up on the dash? Clearly there should be no leakage around the injectors, really can't say how this would affect performance.
Whereabouts are you?
All the best
Loose - not close, compact, or tight in structure or arrangement
Lose - to part with or come to be without, as through theft, accident, negligence, etc.