backfire and loss of power

[nadeemkhan]

my 91 525i backfires and looses power on fast accelerations, uphill and around 50/55 mph. I had complete tuneup done with plugs changed but no improvement...

[Bruno]

- Did you check vacuum leaks?
- Did you check coils?
- Do you have an engine code?
Can you read the engine codes anyway?

What was done in the complete tune up?