I tried doing a search and found a guy with the same problem but he never had an answer in his thread.

In hot afternoon, city driving the engine will suddenly kick into a mode where it won't go over 1500 RPM. If I let it cool down for awhile I'll be able to drive again.

I drove it this morning(lower ambient temp) and it was fine, but did it in the afternoon.

Kind of annoying when I'm in the middle of an intersection.

Thinking it could be:

Thermostat
Coils?

Open to any and all suggestion.

Thanks!

 

Any info on what year and model your car is?

 

Sorry, wow. Can't believe I missed that.

87 GXL non-turbo 5sp.

Um, modifications to the emissions and ac. Not sure exactly what the previous owner did to it in regards to the emissions.

 

I changed out the thermostat with an OEM unit and although it didn't cut off to 1500RPM while driving, I did have it happen when I restarted the car.

Anyone have any ideas?