Idle shoots to 1800 rpms, 3 seconds after startup. CEL flashes 3 times

[1995COBRA]

Hello All...., I had my 95 Cobra parked awhile, but would start it up every so often. Until couple months back, I started it up.., and the idle rev'd up to 1800 rpms for about 20-30 seconds.., then gives a BIG cough, like it is almost going to die, then comes backs to like, then the idle stays normal at about 850 rpm (the runs great!). It is just everytime I startup, it has that high rpm hang for about 30 seconds or so. I have changed several parts off my other low mileage Cobra (which is running perfectly). Changed out IAC, TPS, cleaned MAF..., still same effect. Even put my tune back to stock, still no luck. I have checked the codes with the car OFF, and nothing sticks out besides 511, 565, and 542.. What I did notice, is if I unplug the MAF sensor, and startup the car.., I do not get that high rpm rev issue. I have only cleaned the MAF, but next step is probably to replace it. I just wanted to get alittle feedback, before I start going buying parts that I don't need .

Thanks for the help...any help is well apperciated.

Thanks
Leo

 

[1995COBRA]

bump.. still haven't found the issue. Any thoughts ?

Thanks
Leo

 

[Noobz347]

It appears you've looked at the usual suspects and even pulled codes...

Here's a shot in the dark: Pull the vacuum line from the fuel regulator and see if you see or smell fuel.

 

[AeroCoupe]

Code 511 is a ROM failure or there is a chip present i.e. the car is tuned.
Code 542 - fuel pump open circuit pcm to ground
Code 565 - Canister purge circuit failure

My guess here is the ECU has crapped the bed.