My car want's to idle at 2k+ plus rpm, even with the clutch in. It failed emissions, said lots of unburned fuel, and my gas mileage went to ****. Whats wrong?

Manual B16A in the del Sol.

 

Have you checked the IACV? Mine was idleing at 2-3k and I replaced that and it sits about about 1200 now... I picked up one at the junkyard for $6

 

Can you give us more info?

When did this problem start? CEL's? Any recent modifications or work done to the car?

 

Can't post CEL's cause it won't tell me what codes it's throwing. I'm thinking possible bad ecu. Start the car up, cel is lit, and if you jump the plug to get it to throw codes, it stays solid. Tried disconnecting the negative and removing the ecu and the backup fuses and it won't reset, or the light comes back on immediately and still idles high.

 

The CEL will stay solid if there are no codes stored when you are jumping the service connector.

Are you sure you are jumping the harness properly? A lot of people try to use paperclips--- a lot of paperclips have a coating on them and they won't conduct.