What can I check? Air control valve is functioning, EGR valve cleaned and tested with a vacuum meter, plugs, wires and distributor cap installed. What else? Can't find any broken air hoses. Anyone any ideas? I can't pass Colorado emissions until I can get this solved. Thanks for your time.Roger

What can I check? ....

 

Compression?

 

I use a tank of 10% ethanol fuel (Union 76, where I live) every now and then if my vehicle's running rough and it may help clean something out a bit, I imagine that it does help reduce dieseling or rough running sometimes (or I'm just superstitious)

sounds to me that you may have a vacuum leak... What i would do in this case is take my propane torch turn it on.... DO NOT LIGHT IT... and run it around in your engine campartment, like at intake manifold, down the vacuum lines, and even your injector seats and seals... if you find your engine smooths out then you found your leak...

 

What are you failing on your emmisions test... HC, CO, NOX, well thats what test for in most states.. if you post your readings i may be able to help a little bit more

it could very well be a vacuum leak. i accidentaly unplugged the p/b 4wd hose when i did the passenger side axle. had the same rough idle and engine shake plus my 4wd didn't work. sometimes the leaks make a hissing sound, but it can be difficult to hear over the engine noise without a mechanic's stethoscope.

I am crossing my fingers for a clean trip thru emissions for ya! This is a pretty nice little RU if you ask me!

 

The CO was 20.6XX out of an allowed 20.000 the first try and nearly double allowable on the 2nd attempt after new plugs, wires, etc.

 

A new 02 sensor and reset of timing should help alot, just a seat of the pants indicator would agree. Timing was about 8 degrees off and the o2 was BLACK soot covered. Seems this car may have spent some time at a lower altitude or somebody didn't plug the test connectors in while setting the timing the last time.

Now to fix the darn oil pressure gauge...

 

Thanks Shawn!