Hi my 305 TBI is having issues. When left at idle the idle slowly drops after engine is almost to operating temp. The idle will drop until it goes so low it wants to stall it will surge back up a few times then ultimately stall. When driving it will constantly have fluctuating rpms unless at full throttle. I'll be going down the road at any speed and my rpms will go from normal drop like its gonna stall then surge back up. I have hardly any power unless full throttle. Already done full tune up replaced the tps which took it back to perfect for a month then back to these symptoms again replaced the tps again no help. The I just cleaned egr and iac. I'm lost please help I don't have another car right now and need this to work correctly.

 

Might want to start by getting hold of a scan tool. Stuff like this is often difficult to diagnose without seeing things like the computer sees them.

That being said, it does generally fit the symptoms of a vacuum leak. PCV line and power brake booster line being the most obvious and biggest offenders if they are leaking. But it could be just about anything that's got a vacuum line running to it from the engine.