RepairPal is your advocate for car care advice and guidance

Q: won't pass smog high NOX mildy rough idle when warm on 1995 Chevrolet Blazer

Rookie cbe0621eac06868b3efe0d8d1d3611e23c60d3114864ea2ec19a68cfbd3eebab
new egr-cat-O2-injectors sensor-MAF-good fuel pressure-vacuum-distributor- no diag codes- 6 months ago had O2 code and MAP code- replaced both
No car image 94a1663db56199c5353592009e34aaa51078a2469bed068bb8d6f0ba43accf97
Get a Repair Estimate
Guaranteed by certified locations nationwide. Learn more
RepairPal estimates are guaranteed at over 1,700 quality certified locations nationwide. Learn more
AFTER you check and clean the EGR system , some other things to check would be ; engine temp.(195-210F) , make sure fan clutch is operating properly , IF it was an aftermarket cat. make sure it is in the original location and proper size I know CA. laws diff. from fed.. I do emissions inspections in VA. and I've seen many aftermarket cats that are 'legal' to sell , and supposedly meet 'specs' but can't clean up the exhaust the way a factory one would. Make sure your dist. timing isn't advanced to much. Check that the advance is working properly. If it's a high mileage engine, excessive carbon build-up on the pistons could cause high NOx.I believe GM has a 'top engine' cleaner for that issue- when used as directed I've seen good results.PLEASE , check the EGR first.(hint on the converter- if you have access to an infra-red thermometer you can check the cats temp and some of the other things mentioned.)
Didn't find what you were looking for?