Need Serious Help - Car driving me crazy

[cgreiner]

Sorry for the long post...but please read...

I own a 1987 Supra Turbo that has been giving me a bit of trouble off an on. The car is mostly original and stock, with the exception of a rebuilt engine with only 45k miles on it and an aftermarket thermostat and air filter. I love the car, but am sadly having a bizarre problem with it.

Typically, but not 100% of the time, if I am driving the car in or just after it rains it seems to stutter. It will start fine, but while driving it will periodically partially cut out and the check engine light flash. By this I mean that the RPMS seem to drop. The car usually idles at about 1000 RPM but when this occurs the idle drops to 500 RPM, the car exhaust smells awful and it appears to want to stall. Now, this does not only happen when idling but also when in gear and driving. If cruising along, it some times stutters, jerks violently a few times and drops the RPM about 500 from where you were cruising.

The car is a 5 speed manual transmission and red lines at 5k RPM. I have noted that when this occurs, if I punch the gas and rev the car high (4k RPM) it will recover and ride smooth for a few minutes. However, the recovery is usually a fairly violent lunging motion. I can also typically avoid the problems if I cruise between 4k-5k (careful not to redline).

So what is up with that???

I know I have a 2003 Suzuki SV650 that had a similar problem. After $500 at a mechanic who swore that is was a loose exhaust the problem returned upon the first rain. I then found, via a online forum, that there is a little known drainage hole in the engine block near one of the spark plugs. The problem - this hole was clogged. The solution - a $0.10 pipe cleaner and some rubbing alcohol. Apparently, water was backing up and killing the spark thus the lunging, jerking and wild ride.

So, is there the possibility of something similar with the Supra? They are known for valve cover seal leaks and oil getting into the plugs and I do have a slow oil leak some where I can not find. It sure seems like some sort of spark plug issue to me.