I have a 1987 Salon with a stock 307.
When the 307 reaches normal operating temp the car runs very rough (valve clatter, no power, hard gear shifts). Car runs fine when cold. Local mechanics cant solve issue.
Any suggestions?

 

It could be the transmission. I have an 87 cutlass 442 and the tranny torque converter was prematurely clamping when the engine was hot. I had no signs of problems on a cool engine, so this might be your issue.

Find a "Transmission Mechanic" (not firestone...jiffy lube...etc) and tell him that there might be an issue with your tranny and torque converter.

He will most likely ask you what the year is and when you tell him it's 19 years old he's probably going to recommend a rebuild if it's showing any problems...because sooner or later your going to cause your car damage and lose your investment or force to get a new transmission.

 

Thanks for the info. You are right on the money. The solenoid for the Lockup Torque Converter had malfunctioned. I simply unplugged it and the car runs like a top now, with the exception of the excessive fuel consumption. I'll get the solenoid replaced soon. Thanks again.