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 Juan Crespo Your Own Question
Juan Crespo
Juan Crespo, ASE Certified Technician
Category: Chevy
Satisfied Customers: 1524
Experience:  A.S.E. Master Technician, Advanced Level, Emissions - Asian, Domestic, & European
19298667
Type Your Chevy Question Here...
Juan Crespo is online now
A new question is answered every 9 seconds

I have an 09 silverado i chamged the number 1 lifter now the

Customer Question

I have an 09 silverado i chamged the number 1 lifter now the miss is gone at idle but the oil pressure is bouncing from zero to less than 40 when u rev the motor the miss comes back ive check the injectors amd coils and spark plugs why is it doing this does it have to do with the stabilitrack?
Submitted: 1 year ago.
Category: Chevy
Expert:  Juan Crespo replied 1 year ago.

Hi there. Thanks for using our service.

I can probably help you, but first I need to know a little more about this issue:

  • what model, size engine and type of drive in your Silverado (or your VIN?)
  • what compelled you to replace that lifter? Which one was it, intake or exhaust?
  • is the check engine light ON? If so, what codes are there?
  • is the Stabilitrak warning light ON?
Customer: replied 1 year ago.
I had a mis in number 1 cylinder amd the service stabilitrak and traction control was dinging so i replaced the lifter it was the very first on after i put everything back together the check engine light went off amd it idles smooth but oil pressure is no good and bounces from 0 to less than 40 if u rev the motor the miss comes back. The truck is 5.3 silverado z71 LTZ with automatic transmission
Expert:  Juan Crespo replied 1 year ago.

Thank you for that information.

If your truck is equipped with active fuel management (AFM) there is a TSB from GM that tells you to replace the lifters in pairs as well as to perform the following procedures using a dealer-level scan tool:

Cylinder deactivation (Active Fuel Management) system compression test in SI. If the running compression of the misfiring cylinder stays below 25 psi regardless of the AFM solenoid being commanded on or off, the AFM lifter is mechanically collapsed/stuck or unlocking as soon as the engine is started.

* Cylinder deactivation (AFM) valve lifter oil manifold diagnosis and testing in SI. If the test above isolated a possible AFM lifter concern, it will lead to this test, which tests the VLOM (Valve Lifter Oil Manifold) for proper operation. SI states a limited amount of air will leak from the bleed holes and outlet ports even when solenoids are off, and compare the amount of leakage to verify all 4 solenoids are operating the same. If it isolates a concern with the VLOM, replace it and re-evaluate the concern.

* If the tests above isolate an AFM concern, or if no rocker/valve movement is noted with the valve cover removed, follow SI repair procedures to replace the pair of lifters for the related cylinder. Before installing the new lifters, blow out the related lifter control oil passages with the old lifters removed. Also, inspect the VLOM oil filter under the pressure sending unit for debris/sludge and clean or replace as necessary.

* NOTE: Please follow the diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

Best Regards.

Related Chevy Questions