I saw a few suggestions concerning MAP Sensor maintenance on other vehicles, so thought I'd give them a go today.
Suggestions were along these lines:
-The MAP Sensor is connected to the intake manifold using hard plastic tubing. Make sure there are no cracks or damage to this hard tubing and also make sure there's nothing clogging up the hard tubing (oil, dirt...). Tubing damage or clogged tubing could effect sensor readings
-Use some thottle-body cleaner to clean out the small inlet on the intake manifold where the Map Sensor's hard tubing attaches. Oil, dirt there could effect sensor readings
-Remove the MAP Sensor from its bracket and spray some electronics cleaner in to the port on the Map Sensor where the hard tubing attaches so as to remove any accumulated oil, dirt there which could effect readings.
I wasn't getting a code for the MAP sensor, but I did recognize that it was probably original from the factory, 17 years old, and the port on it had never been cleaned (!)
So, rather than getting sensor voltages or messing around with electronics cleaner, I just went to NAPA today and got a replacement Delphi unit for around $65.
The original hard plastic tubing to the sensor looked to be intact with no cracks or damage. It seemed to flow air ok, but since it was likely 17 years old, I just went ahead and replaced the tubing rather than attempt to clean out any internal residue with some kind of spray.
I also bought a selection of new rubber connectors to fit on the end of the tubing where it connected with the Map Sensor and the intake manifold. The old rubber connectors were likely, again, 17 years old, very oily and -- to my surprise -- didn't seem like they fit tightly where they connected the plastic tubing to the MAP Sensor port or the intake manifold port. So they may not have been 100% and sensor readings may have been effected as a result.
And then I used a lot of TB cleaner and long cotton swabs and cleaned out the port on the intake manifold.
Once I got everything MAP Sensor-related cleaned-out or replaced, I reconnected the battery and took a drive. It seemed that throttle-response had improved and that the engine was missing the "deadness" I had been getting for years on partial or full throttle application (you'd open the throttle and it seemed like not enough, or too much, fuel was there and/or the computer had seen fit to somehow retard engine performance).
Anyway, I'll see how things go after all this. If you have a YJ/TJ and never before messed with the MAP sensor or its tubing/rubber connectors, you might want to give all that a look and cleaning (or replacement -- parts involved are fairly inexpensive in this case)
