Dash is probably failing capacitors.
The rest sounds like bad ignition system components. Have you done plugs, coil, wires and distributor recently?
I have an intermittent problem with my 535. Doesn't matter hot or cold. Various parts of the instument panel quit working. Once it was the speedo and odometer. Another time it was the fuel gauge. Most often it it the computer display at the base of the cluster. When it runs, it runs GREAT and I've checked for codes. Clean with 1444. When it runs bad, it starts hard(fires, but won't stay running). I get it running and it acts like the ignition keeps dying, but refires before it quits (usually). Sometimes driving down the highway, I get the same scenario. It will lose power for a fraction of a second (check engine light flickers) and it comes back to life. I'm sure it's an electrical problem but don't have a clue where to look. It hasn't let me down yet, but it's getting worse. Please help.
Dash is probably failing capacitors.
The rest sounds like bad ignition system components. Have you done plugs, coil, wires and distributor recently?
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I have not done anything to the car recently except a valve adjustment and oil change. I really doubt that it's secondary ignition related since it is so intermittent and runs perfectly when it's not throwing a fit. I think the dash is related to the electrical problem since they both started happening at the same time. I may be wrong though. I'm thinking more like broken wire or bad connection somewhere.
My instrument panel is similar, i changed capacitors though, even used ones with higher ratings.
The problem still remained a few days later.
No help, but thought id mention it
11/88 535iA
I experienced a similar engine problem in both my '87' 535is and my '94' 525i. Both times it was a failing Crank Position sensor. It's easy to test this sensor if you have an Ohm meter and a Bentely book. Can't help with the guage problem except to say that my 535 ran perfectly with a dead tackometer. Good luck!