I picked up an '89 190E for my kid. It's in very nice shape, only 75K, one owner. There's been a few simple troubles so far - stumble and stall when cold and occasionally dead acceleration from a stop (found a split vacuum line at the EZL) and an intermittent wiper operation (bad fuse).

Anyway, when fiddling around to find what might have been causing the stumbling, I noticed there was no EGR valve. There's an un-machined boss on the exhaust manifold where it should be. I also found that there was no air temperature sensor on the air intake. Again, there's a casting for it in the plastic but it is closed (as in, the hole is completely filled in).

Come to think of it, I'm not sure if there was even an air pump, I'll have to look next time she stops in.

All the auto parts sites list these items for an '89. Is this unusual? Seems to me an 89 should have all that stuff!