Poor gas mileage and rough idle in HX civic. Had a coupe CEL lights so I investigated the EGR. COMPLETELY CLOGGED. Every cylinder clogged!!!
A wire brush, a shop vac, some carb cleaner, brake parts cleaner, and 30 mintues later it was running perfectly! Amazing what a difference it made. most people claim to go from 34 to 38 mpg with this cleaning on cars with 150-200k miles. Wonder what results I will get?