ChrisLS40094

I just noticed today that there seems to be a hissing sound around the intake and some of the vacuum hoses. Could a vacuum leak possibly cause the symptoms i described earlier?

The throttle body was thoroughly cleaned about 1,000 miles ago. I checked the error codes again last night after seeing the check engine light come on again. This time I got codes 14 and 22.

It is definately the engine and not the dash. The engine starts normally, then after a few seconds it begins to race, seconds later it will rev down to about 600 RPM's, another few seconds later, back up to 1500 RPM's. This seems to happen more often with the AC on and on rainy days, although it has happened on dry sunny days too, just not as often.

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. :)