Hi,
I've been watching this forum for ages but have just joined up so apologies if this was previously covered by someone else as I've an annoying issue with my Mk5 BWA engined Gti in completely standard spec.
The car has approx 120k miles on it and I've loved every minute since I bought it. It had the turbo replaced under aftermarket warranty at about 70k (seized wastegate when I bought it due to one previous owner not revving it - weird I know!)
The symptoms for the last 1k miles are as follows:
1. The temp gauge sits at about 1/4 position during normal driving and only increases to mid position on the gauge after a while of idling or in traffic but drops back as soon as normal driving is resumed.
2. At approx 70mph on a motorway, there's a slight lumpiness or miss which is noticeable even in cruise control and during accelerating but it's not enough to slow it down. This is regardless of hills or flats, warm or cold weather but the temp gauge is at about 1/4 position as per above.
3. Occasionally when it's warmed up it suddenly seems to not accelerate too well as if it's gone into soft limp mode (can be cleared by restarting the engine) but no engine warning lights present.
The air filter, MAF, DV, PCV, fuel filter, fuel pump cam follower and plugs have all been replaced, and it seems to run perfectly when it's cold and at idle, with no whistling etc.
I've replaced the temp gauge sensor too on the battery side so I assume the ECU temp sensor and/thermostat within the water pump need to be replaced to sort out the erratic temp gauge but not sure if this will sort issues 1 and 3. Possibly coil packs but why would this only be when warm, or any other suggestions? Someone also suggested an issue with the Charcoal cannister being expired but I can't see why so I'd appreciate if anyone else has any experience of this or has any firm ideas as to the cause.
Finally, I'm curious about the Superchips Bluefin remap and whether a) it might resolve (bypass) the above issue and b) if the above issue is resolved is it a worthwhile upgrade if everything else is standard, so any thoughts on this would be appreciated too. Unlike other systems I like the fact that this one can be easily reversed back to factory settings by the owner although I accept that it hardly needs more performance anyway!
Thanks in advance
