Car Questions
RepairPal is your advocate for car care advice and guidance

High hydrocarbons

(1995 Chevrolet 2500 Pickup)
in Hagerstown, MD on May 09, 2018
Trucked passed emissions except for gas cap
Took truck back 1 month later and it failed
Hidrocarbons went from 10 - 765
Plugs and rotor were just changed but can't figure out as to why the hydrocarbons jumped so high
Catalytic converter passed so it can be ruled out for repair
Any suggestions ??
What seems to make the problem better or worse? Truck has No problems runs great
How long have you had this problem? 1 month
Tags: chevrolet, 2500 pickup
Ask a Question
Displaying 2 answers & 1 comment
Popular Answer
Hydrocarbons are simply raw or UN-burned fuel. Simply perform diagnostics on any item that could cause the fuel not to burn correctly. Start by checking for incorrectly installed or cracked spark plug. If they HC was good before the tune up then recheck the tune up work. Good Luck.
Sign in to reply
on May 10, 2018
I replaced plugs and dis cap. The readings was the same a 3ed time.
A lot of items can contribute to this. Can you come by the shop and Ill listen to the engine and give you some advice?
Sign in to reply
Get a repair estimate
RepairPal estimates are guaranteed at over 2,000 quality certified locations nationwide.
Or interested in getting a repair? Find a Shop

Similar Questions

View answers to similar questions from RepairPal's community of auto experts and enthusiasts.
Replaced egr, vsv, cleaned oxygen sensors, mas, replaced vacuum hoses ... still get code p0402
Didn't find what you were looking for?