124 with 3.2 motor massive surging problem got me stumped

[BeezerBob]

My 93 300E with 3.2 four valve ran great all winter. Once it started to get warm out, the idle began to surge from almost dying to about 1500 either after idling in traffic or heat soaking for a bit after parking. When it was somewhat cool out the car would begin running fine once it cooled a bit. I have read numerous posts on this problem but nothing I read in any of those worked as I have replaced or checked the things recommended in those posts.

Now that it's over 60 always, the idle surges from almost a kill to 1500 or so all the time. It also seems like it's running lean on take off and at speed. I have replace fuel filter, plugs, OVP, checked for vacuum leaks and found none. The upper wiring harness appears to be almost new.

Before I bought the car a significant amount of work had been done at a shop. I don't know the details but the MAS appears new and like I said before so does the wiring harness.

When I first got it the spring that helps close the idle micro switch was broken and the idle was accordingly high. I have repaired that.

The fuel pumps are a bit noisy and I have ordered new ones but I don't know whether that could even cause the problem.

Any hints from anyone as to what the problem could be.

Is there a point at which I have to worry whether the car will get me home?