Mark McCulley wrote: > > Have you checked thoroughly for vacum leaks? Greetings. Sorry for the delay in responding Mark. Yes I have checked for vacum leaks. Every conceivable place that could leak. Evey time a technician looks under the lid they remark "sounds like a vacum leak" but none to be found. Picked up a can of Liqui Moly Vacum Leak Detector, will show a drop in idle if a leak is there. Not as messy as WD40 etc. No leaks detected. > It might be helpful to hook up a voltmeter to the output of the O2 sensor Hooked up the meter to the O2 sensor plugged in. Ignition on .45V .With engine started it slowly rose in a uniform fashion until the sensor kicked in and appears to be operating fine. Lots of cross counts from .2 to .8 > You can also measure the "dwell" on the idle stabilizer Haven't had a chance to try this. Have to find a copy of Probst' book. > >downshifting, back pressure. > What exactly do you mean by "back pressure?" Is your catalytic converter > shot? By "back pressure" I mean de-acceleration from a high rpm, 4000 or so. The exhaust manifolds seems to push a lot of pressure which I am sure is normal, but there is a strong vibration when this happens. The "cat" is only a few months old, but muffler has a small hole and it sounds like the baffles inside are coming loose. Can the muffler cause a strong vibration? Other problems are surfacing, but its late, so I will continue on another day. Thanks. Randolph. |
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