failed smog at 25mph

[88rangerhead]

Went to smog my truck today and NO failed at 25mph.
So max for 15 mph is 1031 and average is 478 and I read 865. That part passed right in the middle.
Max fort 25 mph is 891 and average is 393 my truck put 1051 out and failed the test.
Shop is trying to charge me more then what I am willing to pay to just diagnose the emission system and that isn't including repairs and after repairs that is not guarantee the fix. Tune up was just done last week aside from the distributor and coil but cap and rotor were done. Any tips on stuff I can do myself to help it pass. The cat was done in 2011 and I have about 270000 on the truck now and its my daily driver for work (roughly 90 miles a day.)

 

[Dirtman]

Move.

 

[88rangerhead]

Trust me I would love to.

 

[elscotto80]

Where are you thats still doing emissions on a 30+ year old truck? After a vehicle is 20 years old in MD we can register as historic, no emissions or inspection.

 

[Uncle Gump]

So... they put the vehicle on a chassis dyno? When I did emission testing in Michigan... it was no load testing.

I assume you're talking PPM HC... what was the CO level?

 

[rusty ol ranger]

Change your O2. Spicially with that many miles.