Engine light comes on going down hill 55plus mph

[lyv wyr]

Hello all,
I've got a 95 Z26 3.1 w/ 228000 miles. Had it since new. Looking for a little help diagnosing my problem.
My engine light comes on when I go down a hill exceeding 55-60 mph when I get all the way out of the throttle to let it coast. If I'm traveling 50 mph or under and go down a hill the light will not come on. Same situation going down the interstate, if I'm going 65 + mph with my cruise on for instance and turn the cruise off and get all the way out of the throttle and let it coast if I'm getting off on a off ramp or get blocked by a passing car the light comes on, but if I'm going under 55 and do the same thing it won't come on. Seems like with both examples if I get out of the throttle, but then lightly give it some throttle every few seconds like burping the gas, the light won't come on. Even when the light does come on the car seems to run fine, no great change in gas milage or anything. Also after the light comes on if I shut the car off and start it again the light will not come on until I go through the same situations.
Any guesses?
Thanks,
Ryan

[3X00-Modified]

EGR is failing or dirty... Try cleaning the pasages to the intake and see if that fixes it.

[DTMAce]

Agreed. Need to remove the EGR valve and remove the throttle body, and clean the breather/passageway from where the EGR mounts as it goes into the upper intake manifold. Use a small diameter bristle brush, or even a wire clotheshanger with a small loop in the end and run it through. You need the throttle body out of your way so you can clean out the debris, you don't want that to go down into the engine. These SFI engines have a majorly common problem with this. I would recommend this prior to spending money buying a new part.

[Styluss]

Cleaning this and the throttle body can have HUGE positive results for your car. Be sure to clean the inlet for the EGR valve not only on the engine but on the EGR as well, clean the throttle body front and back and remove and clean the throttle body top plate while you have it all apart. As an example when I bought my 4Runner I had an issue with the idle. It sat at about 400rpms at in gear idle! I removed the throttle body top plate and cleaned it and the throttle body as they were both filthy. The little air hols for the vacuum tubes that come into and out of the throttle body were nearly completely clogged shut. After putting it all back together my in gear idle rose 400rpms! The 4Runner is different than a Beretta I know but the example holds true. Just as Ace said, do this before you spend any money as it may very well solve all of your issues with just a can of throttle body cleaner spray and a towel.

[lyv wyr]

Thanks for the help guys, I will def give these tips a try before I swap out the EGR. Should I just use a brush and/or clothes hanger or should I also use some carb cleaner as well? Sounds like a pretty easy fix!!

[Money pit Beretta]

Yes use some carb cleaner and a hanger(there is no way to get a bush in the port all the way to the other side). Just for fun you can spray the underside of the EGR. That will make sure that ports are free to move.