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Matt
Matt, Mechanical Engineer
Category: Ford
Satisfied Customers: 21866
Experience:  BEng hons Mech engineering, in auto industry 22 years
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Ford cmax petrol 1.8L 54 plate milage 98k vin

Customer Question

ford cmax
petrol
1.8L 54 plate
milage 98k
vin no:wfomxxgcdm5j89682
While driving engine fully warmed up, system fault displayed on instrument cluster suddenly. After a few miles followed by engine management light, vehicle starts to hold back with rough running and goes into limp mode. Switched vehicle off, reset again after a little while problem comes back again. Connected to the scanner, fault code P2008, carried out research, replace vacuum solenoid valve, okay for 1 month, vehicle comes back again same symptoms this time with fault code P0106,P2110. Replaced map sensor, borrowed donner throttle body still no joy. Checked all vacuum pipes all were ok, any ideas? thanks
Submitted: 4 months ago.
Category: Ford
Expert:  Matt replied 4 months ago.

Hello

I suspect that the MAP fault is being driven by the throttle issue

as if the throttle hammers back and forth it can create issues with pressure fluctuations in the manifold

So I'd say the next think to check is the condition of the throttle wiring for any damage , hard sections or chafed insulation

also

This could be an airleak after the airflow meter, any air dragged in here isn't 'seen' by the ECU and so not compensated for and can lean the engine out and can also allow the engine to rev up when not desired causing rough running.
As its a mechanical fault it tends not to turn on the fault light and you can sometimes hear a 'hissing' noise with the engine running.

Check the hose clips for tightness and inspect the trunking for any cracks or splits and also all the vacuum system, the small bore pipes and fittings for cracks and missing parts.

The best way to locate a leak is to have the engine running and warm and then spray lighter gas /propane or brake cleaner around each joint in turn. If the engine rev's up you've found your leak.
Now you might think that spraying lighter gas around a hot engine isn’t wise, however the flash /ignition point of gas is about 400°C so you need a naked flame or spark to set it off and I’ve used this method for many years without incident.
Work your way through each possible joint one at a time and you should find it. I use a slightly flattened piece of brake pipe and some rubber hose from the can of lighter gas to provide a spraying 'wand' and allow a direct blast of gas into each area, especially those difficult to reach with large implements.