ECM replacement

Ok, I've got a 96 S-10, 2wd ext cab, 67k, "w" vin.

I have been having strange idle problems and this is what I have replaced so far:

EGR
IAC Valve
IAT sensor
Coolant temp sensor
TPS
TPS Connector
Plugs
Cap
Rotor
Fuel Filter
Vacuum lines
Cleaned MAF

So, I was still having the same problems, in park/neutral the idle would jump up to 2500-3000 and just sit there, you turn it off and it would diesel on. now this was an intermittent problem and wouldn't happen all of the time. So I finally took it in and had it analyzed and the local chevy place is telling me that My ECM is bad and needs to be replaced, for the nice price of $761.66.

Now my question is how hard is it to replace an ECM? Do you have to pull the motor? or is it just routing the harness? And if I do replace it, do you have to program it once it's in? The service manager was telling me that, that price includes parts, labor, reprogramming and tax.

Changing the ecm on that car should take less then a half hour. Its the box on the inner fender behind the battery. It looks about like this http://partimages2.genpt.com/partimages/808744.jpg. You might have to get it programmed to your car before it will work though. Looks like its about $170 at napa, and they list 2 diff ones. You can get a replacement at a junkyard for less, and it may not require programming, but you never know what you are getting for junkyard parts.

Changing the ecm on that car should take less then a half hour. Its the box on the inner fender behind the battery. It looks about like this http://partimages2.genpt.com/partimages/808744.jpg. You might have to get it programmed to your car before it will work though. Looks like its about $170 at napa, and they list 2 diff ones. You can get a replacement at a junkyard for less, and it may not require programming, but you never know what you are getting for junkyard parts.

I've used Napa twice for the ECM on my truck.

About $250.00 with programming. (I got a discount on the unit, plus $125.00 to flash the program; Napa did the whole set-up)

If you buy a salvage yard unit, you'd better get it from the exact same vehicle as yours, otherwise certain options may not work.
These ECMs are used on a variety of vehicles, including Tahoes, S10s, asnd so on (with differnet 3nignes like 4 cyl, 6 cyl, and 8 cylinders)

If you "do-it-yourself", do not forget to remove the knock sensor off the bottom of the ECM. Remanufactured units don't come with it.

Thanks guys some great info, especially Mike2004tct, I didn't know about the knock sensor. I picked one up at O'Rielly for $130 and a $70 core (and it comes with a lifetime warranty), then they can flash it and that's $69.99. So after the core charge I am out about $200 bucks, way better than the $761.66 the local chevy dealer wanted to charge me.

I've used Napa twice for the ECM on my truck.

About $250.00 with programming. (I got a discount on the unit, plus $125.00 to flash the program; Napa did the whole set-up)

If you buy a salvage yard unit, you'd better get it from the exact same vehicle as yours, otherwise certain options may not work.
These ECMs are used on a variety of vehicles, including Tahoes, S10s, asnd so on (with differnet 3nignes like 4 cyl, 6 cyl, and 8 cylinders)

If you "do-it-yourself", do not forget to remove the knock sensor off the bottom of the ECM. Remanufactured units don't come with it.
and if you use a salvage make sure you get the numbers of the old ecm