ok the low down...89 L98 700r4.. the car runs and idles perfect...

the first #s is my car 12k miles ago which passed. the second line i failed.

@15mph==co2/ 13.4 /12.8 == o2/ 1.9 /2.8 == hc/ 74 /108 == co/ .24 /.38==
no/ 225 /97...........@25mph==co2/ 13.7/12.9==o2/ 1.5 /2.6==hc/ 68 /92==co/ .17 /.28==no/ 188 /125..............failed on hc by 9pts @25mph...

what ive fixed...cat converter in 2000....o2 sensor in 02'....egr in 98'....mass air sensor in 03'....and pcv,cap,rotor,plugs,wires and injectors last week....plus did a diognostic scan and found injector pulsewidth,timing,o2,massair, all perfect . but found a few knock counts...

mods are 160 stat+fanswitch/k&n/msd+coil/flowmaster/built trany with non lockup converter.....so i failed on the hydrocarbons and see a little knock so i assume there is unburned fuel somewhere in there ..what did i miss? thanks guys for any help or thoughts on my problem....

 

What I had to do was drop my fuel pressure a bit,changed the oil,and you might want to put a highrer stat in for the test. If your using a Bosh O2 get a Delco even if you just use it for the test,these items helped me pass.

 

yea,i would try using a 180 or even a stock 195 degree thermostat...help burn up some of that unburned fuel