1994 GMC Suburban • V8 Automatic • 250,000 miles

I have a 1994 GMC Trailmaster (wagon Suburban)
We bought it used, took it in for a check up knowing the brakes felt spongy and that if you brake hard, the truck would die.
We did the following:
oil change, air filter
tune up
replaced front brakes and rotors, rear brake shoes and drums.
replaced idler arm, pitman arm
gear box and coupler (lots of play)
freeze plug (leaking)
radiator cap
oil cooler hoses (leaking)
the power booster
3 port EFI(this part isn't legible on receipt)
$130 worth of fuel injector cleaning.

Well, $1700 later, the ABS light comes on frequently and the truck dies when you brake hard.

Any suggestions would be greatly appreciated.
Thank you.
July 12, 2011.

One problem at a time. For the stalling.
First eliminate all vacuum or air leaks in the system. You may have a bad IAC ( idle air control) but try cleaning the throttle body first. Remove the intake snorkel, have someone hold the throttle wide open for you and scrub the back side of the throttle plate and surrounding bore with an old tooth brush and some carb cleaner. Be sure to spray some into the small holes next to the throttle plate. That should help stabilize the idle. If it still has a problem, replace the IAC.

Jul 12, 2011.
Check for abs codes. As far as braking hard, are you talking about fixing to have a wreak hard or just stop-lite hard?

Clean the throttle-body and iac. Take a look at throttle position sensor.

Jul 12, 2011.
To JDL: fixing to have a wreck hard, or gonna pass my turn hard, or I thought I could make that stale yellow light. But I'd better stop.

The ABS light means (according to manual) that the brakes are working but the automatic braking system is not.

To Wrenchtech - will give it a try. Thanks.

Jul 12, 2011.
Oh no. I see the "codes" are something totally different. Do you have to take it in to the diagnostic machine for those? It is under warranty still I just need to take it into the shop when the ABS light is on I guess.
I've found some sites that describe how to check and replace those things you both mentioned, thank you for your help!

Jul 12, 2011.
Yes, the ABS codes will require a professional scan too to diagnose.

Jul 12, 2011.