hope it's not the transmission
 

after 4th gear and it reaches 3500 TO 3800 RPM , the RPM starts to go down .WHY BAD SENSOR OR SOLENOID

you really have to give more details if you expect anybody to try and help you. maybe give us a schenario when it happens. the more details the better.

it runs ok but after 4th gear and reaches 3500 - 3800 RPM it will not go any further , it's like loseing power and when i bring it back down to 3000 RPM it runs ok something like a safe mode , change optispark and TPS. :confused: just tested on N and it does the same thing.

ANY BODY HOME :judge:

doesnt' seem like a trans issue- if it does it in N also...

Do you have cat's? If so they might be plugged.

stock

Look into the exhaust being plugged or a drivability issue. This doesn't sound like a trans problem.

driveability, like what

took it to the shop and they said it's the transmission, what solenoid would cause this problem. :bang:

anything would help

i think i'm going to sell the car and see if anybodyis that crazy to buy it