I have a 1994 LS400, w/ roughly about 130,000 miles. It seems about 60-70% of the time the car seems to run fine without a hitch. Then there are times, especially on rainy and humid days, that the car just doesnt seem to act normal. For example, when idling, the tach needle fluctuates from about 600 RPM's to around 1500 RPM's. This sometimes happens up to about five minutes. While this fluctuation occurs, black smoke is visible from the exhaust.
So the next thing I do is check for any error codes, and to my surprise no error codes are stored, hmmm, go figure. (This was two weeks ago)
Then today, while driving home for lunch, I noticed the check engine light came on for only a few seconds. Good. Now I can detect an error code and find out what the problem is... To my surprise I am getting error code 22 (engine coolant signal/sensor). This is not a code I was expect considering the car is not low on coolant and doesn't seem to be running hot.
I was initially thinking maybe the MAF sensor was the problem, since that seems to be a popular problem on this forum with similar symptoms to mine, but now I am at lost. Anyone who has any advice where to go from here or has had this problem before would be much appreciated. :)