Very expensive fuel injection problem, help!

[spinedoc]

96 SL500. Last summer on a very hot day the check engine light came on, car still ran perfectly. MB dealer pulled an oxygen sensor code, they said not to worry, cleared it and I was on my way.

Last week, again on a very hot day, the check engine light came on, like last time the car continued to run perfectly. The MB dealer once again pulled a code for the oxygen sensor and said there was an old code stored for the MAP sensor which could be related. Anyway they went ahead and replaced the oxygen sensor but could not get the car to pass their diagnostic tests. They traced it to the fuel injection control unit, they listed it as the ME Control Unit on the invoice. Anyway this part alone costs $2300!! I guess it is a sealed unit and has to be completely replaced. They put my old O2 sensor in and I left it at that for now.

They were able to clear the engine light and told me to continue to drive it normally, but to expect the check engine light to go on. They said I would probably not damage anything, but to bring it back if I had any hard starting or rough idling.

Anyone have any insight to this? It is a rather expensive repair I would like to avoid if I could, but I hate to see the check engine light on all the time and worry I could damage the car somehow if it runs too rich/lean. Any advice would be appreciated.

[RickM]

I would ask to get a copy of the codes they pulled. Let's verify them.

If you have access to a gunson gas tester (or someone with a unit) you can check the A/F ratio to make sure you're within acceptable limits.

I'd also give http://www.programainc.com/ a call and see if they can rebuild.

[spinedoc]

I will call next week to see if I can get the codes they pulled.