Hi
I have a C4 1.6 ( 110 bhp ) with AL4 automatic gearbox . It looks like in idle there is a lack of power. If I stop right next to a pavement curb and I try to get on the pavement , the car cannot go over the curb. When pressing the gas pedal after the car stops it hesitate till it accelerates. I suspected a vacuum leak so I hooked a Lexia and look at the various parameters especially the MAP reading and it shows at idle 540mb and it goes to 240 mb when revving to 4000 RPM. I notice that when I tried to go on a pavement curb ( can not go over it ) the engine can not go over 1600 RPM and the MAP shows 750mb. When it happens and I releasing the gas pedal the MAP reading stays 750mb for 5 to 10 seconds and it looks like the brake servo is not assisted by the engine vacuum and the travel of the brake pedal is much shorter than normal.
I replaced the MAP sensor just for the testing , I am not sure but it looks like it helps a bit.
I leave on a mountain about a 100 meters above sea level and the phenomena gets worth, in compare to driving at sea level. On top of it when trying to accelerate on a steep slope from standing at the beginning the car hardly moves. I didn't measure the fuel consumption but it looks like it increase. The car has 110,000 km.
Another thing worth mentioning is that about two years ago the pipes of the front window washers cracked and a lot of water spilled over the MAP sensor, and the check engine lit, and the idle was rough. When it happened I dried the MAP sensor and the idle gets back to normal, but from time to time the idle was rough and the check engine lit. Turn the car off and on sorted it, and after 6 months I t didn't happened again. A Lexia shows cylinder 4 misfire so I replaced the coil but it didn't help.
The AL4 gearbox never goes to limp mode and seems to be OK
Any ideas how to sort this ?
Thanks
I have a C4 1.6 ( 110 bhp ) with AL4 automatic gearbox . It looks like in idle there is a lack of power. If I stop right next to a pavement curb and I try to get on the pavement , the car cannot go over the curb. When pressing the gas pedal after the car stops it hesitate till it accelerates. I suspected a vacuum leak so I hooked a Lexia and look at the various parameters especially the MAP reading and it shows at idle 540mb and it goes to 240 mb when revving to 4000 RPM. I notice that when I tried to go on a pavement curb ( can not go over it ) the engine can not go over 1600 RPM and the MAP shows 750mb. When it happens and I releasing the gas pedal the MAP reading stays 750mb for 5 to 10 seconds and it looks like the brake servo is not assisted by the engine vacuum and the travel of the brake pedal is much shorter than normal.
I replaced the MAP sensor just for the testing , I am not sure but it looks like it helps a bit.
I leave on a mountain about a 100 meters above sea level and the phenomena gets worth, in compare to driving at sea level. On top of it when trying to accelerate on a steep slope from standing at the beginning the car hardly moves. I didn't measure the fuel consumption but it looks like it increase. The car has 110,000 km.
Another thing worth mentioning is that about two years ago the pipes of the front window washers cracked and a lot of water spilled over the MAP sensor, and the check engine lit, and the idle was rough. When it happened I dried the MAP sensor and the idle gets back to normal, but from time to time the idle was rough and the check engine lit. Turn the car off and on sorted it, and after 6 months I t didn't happened again. A Lexia shows cylinder 4 misfire so I replaced the coil but it didn't help.
The AL4 gearbox never goes to limp mode and seems to be OK
Any ideas how to sort this ?
Thanks