Dealer replaced injectors and water pump and now power delivery and shifts are awful.

[ManiacGT]

So late 2017 my car developed a cold start misfire. I booked the car into the local dealership.

On the way to the dealership the car overheated (amber warning) and as I rolled into the dealer car park I got a red warning to stop the car, which I did.

They diagnosed water pump failure and the misfire as faulty injectors.

Both were replaced and the car returned to me.

The following day under cold start I noticed the car felt lazy and I put it down to perhaps a reset of some adaptations by the dealer.

Several weeks later it got no better and then followed several months of back and forth to the dealer for them to ultimately give up as they could find no fault codes nor detect or understand what I was telling them.

Essentially the cars power could feel sloppy and lazy one day then fairly normal the next.

However DCT shifts were snatchy (used to be smooth) and power drops away after shifts before recovering seconds later. It’s unpredictable and unnerving to drive.

I took the plunge to apply MHD stage 1 and this allowed me to play with wastgate settings etc and putting the setting into low lag improved this snatchy and power drop off but it didn’t make the car as it used to be.

A number of forums are telling me different things about the MHD logs I’m pulling but no one has any idea of the cause.

I took a plunge to replace turbo solenoids but that made no difference.

Vac pipes seem to hold vacuum.

I’ve tested diverter valves and they seem ok.

A bit lost now...

 

[ManiacGT]

So for what it’s worth I thought Id switch around the vanos solenoids today, despite losing one of the circlips somewhere in the engine bay all seemed to go well. That made no difference to the engine issue. One thing I did notice however is how incredibly black and rather syrupy the Engine oil was, So I suspect the overheat has caused damage to the Oil as it was only changed around a year ago and I’ve done very little mileage since. That might play some part in solenoid filters being Clogged which is my next task look at. But I think definitely an oil change is on the cards and can’t hurt.

Whether that’s the root cause of all of this, given everything else I’ve looked at, I doubt it.

One last try now with the dealer to do a full dct and engine reflash in the hope a setting or software fault is at the core.