Well I got my car back today from the local Volvo shop and they replaced the hall sensor. On the way home the engine started to climb to redline. When it is started now it climbs to redline without me even touching the gas pedal- and I have to shut the car off almost immediately. The throttle body air valve looks OK as far as opening and closing and the shop folks came out and replaced the CIS motor, but it still didn't help. I also disabled the AMM to see if that would make any difference and it doesn't. I don't trust the shop at this point as they don't have any answers other than the engine harness is bad -which it is not as it is only a year old !! Any ideas would be greatly appreciated as this car is about to do me in - LOL !!!

First, if the shop keeps claiming the wiring harness is the problem, ask them to identify which wire or wires could possibly cause the engine speed to climb to red line. There aren't any! My educated guess is the shop screwed up something with the distributor or ignition control module. Is the distributor hold down bolt loose and allowing the distributor to rotated to advance the timing and thus, speed up the idle? Is the engine really reving up to redline or just a very fast idle? Since the tach picks up its signal from the iginition system and the ignition system is questionable, the tach could be giving a false reading. jp

Aside from all else, it takes a lot of air to do that. Find the source and you've solved it.......

Your shop should know this.

Shouldn't be hard to do -- probably a vac hose split or popped off a fitting.

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Don Foster (near Cape Cod, MA)

Wild guessing for me, but I'd check all the connections that they might have messed with, especially throttle position sensor. Sounds like the ECU isn't getting the right information from something.
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'81 GLT 245 W/245K; '83 DL 175K

Thanks for all the responses, I did the diagnostic checks on the TPS, CIS and both were fine. What I overlooked was the mechanical screw stop adjustment on the other side of the throttle body. Seems the shop screwed the thing all the way in while they were trouble shooting a problem - no wonder the engine races when it is cranked ($*&^$%$#@$$*(*&*%. Anyway I backed it way off and the car idles fine. Kicking myself because I trusted the shop and didn't look for the obvious myself.