Hi guys, I'm having an issue with my 1994 Astra where I have low power. When I take off in 1st gear it struggles till I get to about 3-4,000 rpm then it has power. It struggles going up slight hills. I have replaced fuel filter, spark plugs, plug leads. Ive also cleaned the throttle body & changed the coolant temp sensor. I've even took it to my local MOT station for them to check my emissions & they said it's spot on. I did notice it had a inline filter Mahle KL14 just below the inlet which I have replaced with a plastic piece of tubing. It's a phase 1 running a C16SE engine. Any help is very much appreciated, thank you.