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ECU Issues

827 Views 1 Reply 2 Participants Last post by  JEEPRZ
Here's the deal: When on the rocks, "gettin' my crawl on" the engine bogs way down if I get kinda hung up--of course. However, if it doesn't stall (if I put the clutch in or it crawls over whatever was slowing it down), then the engine revs way up from about 650-700 RPM to like 1600 RPM. It's a major PITA when you go from a nice put-put-put to "ludicrous speed" (Space Balls reference) especially downhill.

What's the deal? Is this the ECU trying to compensate for almost stalling, is it extra gas in the engine, or do I just need some driving lessons???

In case you couldn't tell from my screen name, it's a 91 YJ with a 4.0 Also, 4.56 and 35's
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Your PCM is opening up the IAC valve, which is essentiall a controlled vacuum leak the 'puter uses to manage engine speed. It is opening it up, trying to raise the idle, as soon as your load lets up, it takes a bit to compensate and bring the idle back down.
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