How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Dan Your Own Question
Dan
Dan, Technician
Category: Buick
Satisfied Customers: 23744
Experience:  Independent Shop Experience, 2 Year Automotive Diploma, & Access to Information Database
17871496
Type Your Buick Question Here...
Dan is online now
A new question is answered every 9 seconds

04 buick rainier,5.3. codes p0300, p0420. and p0430. Dealer

Customer Question

04 buick rainier,5.3. codes p0300, p0420. and p0430. Dealer told me I needed new cats. Any advice?
Submitted: 1 year ago.
Category: Buick
Expert:  Dan replied 1 year ago.

Hello, my name is***** does vehicle run? Thanks.

Customer: replied 1 year ago.
It runs very poorly for a minute or two and then will clear up and run perfect for the rest of the trip
Expert:  Dan replied 1 year ago.

Do you burn oil or have poor fuel consumption?

Customer: replied 1 year ago.
No it doesn't burn oil. Fuel economy is normal. Condition seems to worsen when it is more humid. It only has 115,000 miles on it.
Expert:  Dan replied 1 year ago.
It sounds like the fuel pressure regulator may be leaking fuel into vacuum line. In morning on first start pull vacuum line off fuel pressure regulator, if fuel leaks out then replace the regulator. Let me know how it goes or if you have more questions. Thanks.
Customer: replied 1 year ago.
I will try that.
Expert:  Dan replied 1 year ago.

Ok, let me know. Thanks.

Customer: replied 1 year ago.
There was no fuel in the vacuum line. This morning it ran good at first. A minute later it was sputtering and the "check engine " light was flashing. About a minute later it cleared up and ran fine the rest of the drive. The check engine light goes off as soon as it starts running right.
Expert:  Dan replied 1 year ago.

Try some seafoam in engine which is an engine cleaner. Suck some into vacuum line, let it sit over night to soak, then in morning run in low gear at high rpm to burn out any possible carbon deposits on the valves. Let me know if that helps, thanks.

Customer: replied 1 year ago.
Thank you, ***** ***** try that.
Expert:  Dan replied 1 year ago.

Thanks, ***** ***** updated.