Acceleration Low Rattling Noise -Check Engine Light On on 2001 Volkswagen Beetle

After water pump and timer replacement, coolant leak fixed, I get a low rattling noise when accelerating. Check engine light came on. Has 109k miles. What we can do about it? Great site!

2 answers
I had same problem. The cause was the catalytic
converter.
change the spark plugs & wires .. if that doesnt work... you have to change the distributor