Slow Acceleration 04 Diesel Beetle

[PinkPickles]

I've just recently had a 2nd hand 04 beetle (Pink :> hence the name!) everything was fine until I started going on the national speed limit roads. As I'd hit about 65, the check engine light would come on and it would break for a split second then drive as normal, however after that the acceleration would be incredibly slow.

I took it back to the garage who fixed the problem and other minor things (windscreen wipers, etc.) then took it back on the NSL roads for a quick test. First off it accelerates brilliantly, until I slow down for a roundabout then accelerate again. At this point the acceleration is really slow again.

I know there is an electric system that regulates the road conditions and heat of the engine so it can adapt accordingly to avoid damage or crashes, but I wanted to know if this was normal?

Basically I want to know:
After going over 50+ speeds, then breaking to a stop or almost stop, is it normal for acceleration rate to slow down dramatically?

Please help and thank you!

[SMG]

Originally Posted by PinkPickles

I know there is an electric system that regulates the road conditions and heat of the engine so it can adapt accordingly to avoid damage or crashes, but I wanted to know if this was normal?

The only thing that controls the engine heat is the thermostat, these engines aren't that complex.

Have you changed the fuel filter lately? How many miles on the engine? You might have a clogged IP. The IQ level might be set wrong, could be lots of things.