99 acura code p1491
Code P1491 in Honda/Acura vehicles means insufficient EGR valve lift. Note - this is not the same as 0401 for EGR low flow when you have to clean EGR passage in the intake manifold. If code 1491 is not accompanied with 0401 - that could be faulty EGR valve itself. Try to reset the code, and if it will return soon - replace EGR valve. If, however you see both codes together - cleane the manifold passage before you replacing the valve.
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