Vauxhall Astra Lacking Power

I have a P reg Vauxhall Astra and recently it feels a bit strange a bit lumpy, although not jerky but sometimes feels like it's lacking power especially in third and fourth gear. Tested the spark plug leads and today fitted brand new dealer spark plugs but the car still feels the same, i have to point out no engine management lights come on.

Does anyone have any suggestions to what it could be although the spark plug leads were tested by putting a spark plug into the end of each lead and aiming at some metal to test for sparks, is it still possible that it could be they leads at fault? any advice would be much appreciated.

Thanks in advance

du.

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Yup, that's a 1.2 Corsa.

Joining the M1 at J9 going South, the best I could ever manage with two people in the car was just short of 50mph before I ran out of slip-road. They feel seriously rough compared to the Metro of the same era - almost like you could feel each cylinder firing. And it wasn't just a duff one

- I had several and they were all like that.

Sorry i forgot to mention that it's 1.6i 16v ecotech engine if that helps

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Ooops, I don't know why but I conflated this question with another about PAS on a P-reg Corsa.

Completely wrong! I plead distraction by a house full of smalls.

Oh Guy, you haven't been raiding close lines 'again' have you?

Sorry for 'close' read clothes. :0(

It could be that the catalyst is breaking up and starting to block the exhaust. That will stop the engine breathing properly and reduce power considerably. Other possibilities are a blocked fuel filter or an exhaust sensor that has gone faulty.

Mike

If no MIL lamp and engine runs as normal at low speed / low load and its just at higher rpm / wider throttle openings that it feels "strangled" then first port of call is a cat breaking up (have an emissions test done- if it fails- this is your problem) which is blocking the exhaust or the baffles further back have broken and are doing the same. This is more likely with a cheap replacement exhaust system.

Tim.

Thanks for all replies. Have now had new HT leads fitted along with new spark plugs recently and the car is the same. When the first HT lead was pulled from the DIS module the engine speed did not change and i have know been told that it could be a faulty DIS module.