John Christie

Love my 96 Acura 2.5TL!! But when engine is hot, the tach starts bouncing or stays at zero and the 1-2 shift is harsh. Eventually a service engine light comes on code is P0700 (Trans Control Sys) but I think thats a result, not a cause. Some connection fails when engine hot and trans loses the tach info. Other shifts always good.

TexasHonda

Is cruise control working? A bad VSS will cause a harsh 1-2 shift. Suggest also checking for obd1 codes by shorting the service check connector under the glove box and reading flashes of CEL; long=10, short=1, w/ a short pause separating 1st-2nd digit.

good luck

John Christie

Cruise control works. When condition occurs tach is wacky and hard 1-2. Sometimes it seems to be hunting in the upper gears giving a rough driveability feel - something like a miss. May be a miss. Can a bad coil wire do this? How does the tach get its signal?

TexasHonda

A bad coil, spark plug leads, or ignitor can cause this problem. Coil and ignitor are a unit.

You can check wires at night w/ fine water mist sprayed liberally on wires. Any sparks indicate cracks and need for new wires.

You should also inspect the distributor. I had an accumulation of oil in distributor that caused starting/running problems, but not hard shifts.

good luck

HerTL

Mine tach jumped yesterday when I was sitting at a stop light, and mine also shifts hard from 1-2 also. I just figured it's a "Honda" thing and the hard shift I figured was a lose bolt? LOL I needs all my belts changed and an oil change so...you never know. I just had all my spark plugs changed and a new coil put in so that may be or not be your issue. For a car as old as ours and mine with over 130K I think she runs like a champ.