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Is anyone familiar with how to diagnose a bad power brake booster? I ran across a site with someone who had a rough idle on his 2.5l...he said that it took FOREVER to find (as is my case!!!) and turned out to be his brake booster. His brakes became weak, replaced the booster which also fixed his idle problem. I, too, have noticed that my brakes have felt spongy and weak for some time now, but I'm not sure how to test the booster. Is this something I can test with propane?


Oh, I ran my codes today (KOEO which I pull every month or so) and I'm getting a #23...MAT or manifold air temp. sensor. I'm wondering if this could cause a lumpy idle. The local parts stores (Advance and AutoZone) don't carry it for some reason. It looks just like a coolant temp sensor.



The mat is a temp switch.. When closed it tells the computer the engine is warm enough to go from the rich (startup) mode to the lean (run mode).

If you think the booster is sucking vacuume.. disconnect and plug the vac line to see if the idle improves.
Big JIm <img src="/forums/images/graemlins/pfft.gif" alt="" />

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