Car was brought in from another garage with the symptom that it will idle ok but when you depress the accelerator pedal the throttle butterfly shoots Wide open and the car revs (term used loosely) as if it has a plugged cat.

Parts changed thus far by previous repairer:
Throttle Body (second hand)
Cat
02 sensor (pre cat)
Engine ECU (second hand)

First thing we noticed was an injection time of 12 ms at idle. Checked manifold vacuum and found it barely hitting 6 inhg?
Warm it is better , the peak manifold vacuum at idle warm is 10 inhg and an injection time of 5-6ms
When you do manage to rev it up every now and again on overrun the vacuum peaks at around 18 inhg so the engine is capable of sucking.

What we have done
Timing checked (pulleys not removed to check woodruff keys yet)
MAP sensor tested with mityvac
Exhaust back pressure checked
Fuel pressure checked
Intake manifold removed to check for obstructions
Pedal sensor scoped at pedal and ecu pins

It seems that it could well be the throttle body causing the loss of vacuum as when it does shut vacuum improves but is it a faulty throttle body (original and second hand unit exhibit the same issue) or a load request issue?

Any help appreciated

Regards.

Luke Browne

with a low vac reading the engine will be running very rich, can you create a reading of 18 ing with the mitivac on the sensor to see what the pcm does with the throttle body ??.

not sure how help full this may be but interesting ,

does the scan tool map sensor reading match the mitivac?

if you had any problems with the throttle/ pedal you would have a code for it no?