Hello. I have a 91 Firebird Formula that I just had the egr deleted on. Since getting back from the garage it gets a check engine light once I drive at highway speed, and then it will idle hunt in park and neutral. It will return to normal if you shut the car off for a second. It won’t happen if you don’t hit that speed and cause the light to come on.

the codes I’m getting from the scanner are unreliable and always different every time I check. I pulled both terminals off the battery for 2 hours and there was codes on it before I even started the engine for first time. However vehicle speed sensor was a prominent code being shown, so I replaced the speed sensor and still no change.

1991 5.7 tpi. 60k miles. Had injectors and distributor changed when I had egr deleted.

Some of my dumb guesses now are; bad computer? Egr delete causing it? Any more speed sensor related parts to change?

Any advice appreciated!

Have you blinked the codes , sounds like a code 32

I haven’t done the blinks. Figured a code reader would tell me what it knows.

so based on code 32 you think it’s a map sensor, or egr?

Egr more than likely