First turbo not smooth

The first turbo on my car seems to produce an unstable power delivery. I hadn't really noticed until it showed up on a RR graph, now it's on the back of my mind, i notice it and it is worrying me.

The power seems to fluctuate up and down until the second turbo kicks in, then it's very strong and very smooth. Sometimes the power will cut altogether and then immediately come back in, no warning lights. Thought it might be fuel cut but it has a defender in place and the second turbo is fine.

It's worse when the engine is cold.

I've looked but cannot find any posts that relate directly, praying the turbo isn't kaput anyone have any ideas?

Have you tried an ECU reset?

Do you have any fault codes stored?

Have you tried an ECU reset?

Do you have any fault codes stored?

I just noticed your reply on the way out to change it's oil and thought I would check. So started to drain the oil an took a look.

After shorting the diagnostic points I couldn't work out what the engine light looked like until I found a post with a picture and realised mine didn't work, so I thought I would check the bulb and solder joints.

I don't have a good memory though so I thought I'd better fill the engine with oil before soldering the joints, otherwise I would refit the lights and start the engine to see if they worked with no oil in it.

So I put 3.5l of oil and went to the shed, soldered the joints and came back to find the said oil all over the drive. I'd forgot the sump plug.

Anyway to cut a long story short, I now have an engine warning light and can test for error codes. After counting to 88 I remembered something about a steady flash meaning there are no errors, so no, it has no errors.

To be honest I don't think there's anything wrong with the car, it's just a bit old and sluggish when cold.

I do have to say though, the information and people on this forum make owning a supra a pleasure.