Loss of power

[jeremy fisher]

Hi, my mums 04 plate Astra SXI 1.6 16v (Z16XEP I think) has been suffering from loss of power. It seems really flat and when you pull off the revs drop to around 500 but it doesn't stall just chugs along and doesn't really respond to the accelerator pedal, you have to ride the clutch and give it some revs to get going. Its not that consistent though as she says its not too bad sometimes and will still 'cruise' at 90 on the motorway and a couple of weeks ago it took 5 people on a 400 mile round trip and managed to sit at 80 no probs. I have only driven it briefly and the strangest thing was pulling off and you can floor the accelerator and it just stumbles along. It went to a garage and they wanted to pull the head off and charge the earth because the compression isn't great (105,95,90,115 dry and 115,95,100,130 wet). The garage said it had around 50-60psi but I repeated it myself, I dont think they removed the throttle body to allow it to breath (can't just push the throttle pedal as its fly by wire). I agree that the compression isn't very good but I don't think its enough to cause these problems, especially without clouds of smoke. I tried to get a fuel filter but was told they are 'lifetime' filters??!! The cam timing is spot on and I checked the cat to see if it had collapsed but it looked fine from what I could see. Also I did the pedal test and it showed up 1 code, ECN017258 which a search showed up as "fuel trim sytem rich".
Any ideas or similar experiences?
Thanks
Nick

[blue_peg_16v]

Have you checked all breathers pipes for splits could be a simple air leak