I have a 1998 Mitsubishi Magna, Auto, which has just started to judder under acceleration. The engine rev's fine, but I set off, the car judders, and lacks power. The problem stops after 15minutes, once everything is warm. Any idea's what it is?
There are three things I would like for you to inspect first off. Ensure that the timing is correct and has not jumped, this will cause the judder you mention if it has jumped. Inspect the fuel pressure at the fuel rail. If you have clogged fuel lines and/or fuel filter it will cause a lack of power, especially at start up. Also inspect the vacuum lines and ensure they are free of any cracks, damage or loose connections.