If the information I uncovered is correct, the mass air sensor and the engine-air-in temp. sensor are incorporated into the same sensor. If that is the case, it is indeed on the back side of the engine, inserted into one of the intake manifolds. By putting a jack under the engine, removing the top motor mount bolts and the muffler hangers, I was able to lower the engine a couple of inches and tilt it to the rear enough to reach over the engine and remove it and replace it with a known-good one. The only problem is, it didn't fix the problem.