oh ok then will change air cleaner and of course will take off egr and clean it real good...i will get one of those fuel system cleaners and run the van for a bout a 1/2 hour see if that owrks.chevymaher said:Air cleaner and EGR are a yes to service.
Fuel system cleaner and rub it hard. It is common knowledge a car should be run hard and cleaned out before a test. At least a 1/2 hour on the freeway. Some quarter mile runs really help. Changing the plugs may help some but it don't get the carbon out of the head and off the piston. Which causes higher compression. Which in turn causes higher NO readings.
my catalytic converter is brand neww bought it two years ago, but i will clean my EGR valve change the airfilter and of course run a injection cleaner on it.RECox286 said:If you have never used injection cleaner, shame on you. Shock the injectors with a slight overdose of Lucas' Injector Cleaner.
Then take your truck out on the hi-speed super slab and kick it in the but for a while. If that doesn't help, you may be looking
at a tune up, and possibly a new catalytic converter to clean up the mess. It is possible that the engine has been running rich
and killed the cat. (I had the same problem several years ago.)