Did a paperclip test the other day and found that the T.P.S (along with a couple of other things) was causing my car to run VERY sluggish, as if it was being starved of fuel. Already replaced the airflow meter and the crankshaft sensor without too much difficulty (crankshaft sensor was awkward to undo). All thats left is the T.P.S to replace which should arrive in the next day or two. How easy is it to replace? It's a mk3 astra with a c20ne engine.