Citroen Saxo 1.1 misfire

[Pazdog]

Autodiagnosis says two cylinders low power. Changing injectors and plugs makes no difference. Any ideas?

[dougielogan]

It is either the control unit (coil pack) or if it is adjacent cylinders you could have a cyl head gasket problem.

[homer75]

Worn rings or valve seat probs if it's a high miler. You can do a compression test on each cylinder by using a tool which screws into the spark plug hole. Then you redo the test with a little oil down the bores - if the oil raises the compression to an acceptable level then you know it's the piston rings/ bores that are worn if not then regrinding the valves may cure it. However, unless you do the work yourself or know a tame mechanic the cost of this type of job would be prohibitive on an older or high mileage vehicle. Better to look for a replacement engine.