99 5.4l failed the smog test because of high hydracarbons, anybody have any suggestions. The truck has 146000 miles on it. It is also procharged with intercooler, and has 42lb injectors, running single 3 inch magnaflow dumped after muffler with high flow magnaflow cats. runs great and hasnt thrown an engine code.

 

is it tuned? Might wanta buy a tune and get a custom tune

 

yea it has been dyno tuned, and like i said the trunk runs great. its strong and powerful. im in the process of changing the catalytic converters, its just taking some time because high flow cats are hard to come by these days in california. Do you guys think changing the spark plugs and or O2 sensors will help.