I have just replaced the hose beneath the intake manifold of my x350 4.2. So the manifold had to come off. I used new gaskets before reinstalling the manifold and now the problem is that the engine doesn't run on all cylinders. While running I disconnected the fuel injector connectors one by one and it seems the engine is running on 4 or 5 cylinders (3 on the left bank and 1 or 2 on the right). Did I oversee a connector behind the manifold or are there any other suggestions what went wrong?
Help is much appreciated. Tia.

 

There is a connector on the back of the manifold for the Manifold Absolute Pressure sensor, but if you missed that you'd definitely get a check engine light and some codes showing it missing or failed, or open... something, and it wouldn't affect specific cylinders.

The gaskets... are you talking about the gaskets between the manifold and the heads, or did you actually separate the upper and lower manifolds, which involves a completely separate set of gaskets. Just guessing, but if you got the cardboard gasket between the heads and the manifold, you may have very easily installed the manifold without the gaskets being lined up. The proper metal gaskets have tabs to bend up and hold the gasket in place, and unless you glue the cardboard gaskets down (and probably even if you do) they will shift under the manifold when you install it.

 

Thanks, I'll have a look. Check engine light is on and I get the following warning: 'Restricked engine power' although this may be an incorrect translation as the text is in Dutch in my car. I didn't separate the upper and lower manifold, so only the metal gasket has been replaced.

 

If MIL on, read the codes so you know what the car is telling you

 

Problem solved, I cleaned the connectors of the injectors with contact spray and refitted them. Runs perfectly now so I have ordered a set of new connectors to fit in the near future. Thanks for all the help!