Hi has any one got any idea on this one.
This car is running week at idle only, light throttle and the trim is back to normal. A previous garage fitted a new wide band sensor. which shows lambda at 1.09 aprox at idle and back to 1 at higher revs this is the same on a gas bench. there are no leaks with smoke into the manifold's and i have checked evap egr servo etc. Now the map is to good to be true at 280mbar and if i make an air leak and return the map to 340mbar the ecu adds more fuel and the fuel trim returns to normal.I then noticed that removing the oil cap the map/trim fault clears, so i have replaced the pcv/oil separator valve at the back of the block this made no difference. i realize now removing the cap just makes an air leak.
I have cleaned and reset the throttle body and i have also had a look at the timing. the map sensor is correct I have a vac gauge on it but i tried another sensor anyway So this engine is pulling to much vac at idle making it run weak and causing an air leak makes it run richer.
any thoughts any one.
throttle body? ecu?
Thanks Alan