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 Dave Nova Your Own Question
Dave Nova
Dave Nova, Chevrolet Technician
Category: Chevy
Satisfied Customers: 19452
Experience:  ASE Master Certification. GM World Class Certification
Type Your Chevy Question Here...
Dave Nova is online now
A new question is answered every 9 seconds

Random misfire gmc ***** ***** just had it at a gm service

Customer Question

Customer: random misfire gmc ***** ***** just had it at a gm service kenny ross for this they did a compression check leak down test all came back good they then installed a new rotor cap and gear said the gear was worn and cap had some corrosion didnt go about a day engine light back on codes checked by my local mechanic still random misfires same thing name is joe
JA: Thanks. Can you give me any more details about your issue?
Customer: joe not ***** ***** thats the car
JA: OK got it. Last thing — JustAnswer charges a fee (generally around $18) to post your type of question to Chevy Experts (you only pay if satisfied). There are a couple customers ahead of you. Are you willing to wait a bit?
Customer: yep
JA: OK. Now I'm going to take you to a page to place a secure deposit with JustAnswer. Don't worry, this chat is saved. After that, we will finish helping you.
Submitted: 1 year ago.
Category: Chevy
Expert:  Dave Nova replied 1 year ago.

What year and model is your GMC? Engine size?

Customer: replied 1 year ago.
gmc jimmy 2001
Customer: replied 1 year ago.
4.3 vortech
Expert:  Dave Nova replied 1 year ago.

Does the check engine light ever flash? Do you feel a misfire while driving?

Customer: replied 1 year ago.
it flashed yes that is why i took it to a gm garage dont feel a major misfire but under load seems to be a little not as bad tho after the gm garage replaced the above items in my question
Customer: replied 1 year ago.
what do you think
Expert:  Dave Nova replied 1 year ago.

Have the plugs and wires been replaced recently?

Customer: replied 1 year ago.
not recent maybe about 4 to 5 yrs ago but you would think that the gm garage would have done it if they felt it was needed along with the new cap and rotor gear ,they had the plugs out to do the compression test and leak test so they would have seen the condition of plugs this motor is new only has about 20,000 mile on it thats when plugs and wires were put on due to new engine the old engine head cracked new maf to on it
Expert:  Dave Nova replied 1 year ago.

You would think that the GM garage would have done all necessary repairs, but obviously they missed something. Misfires under load are caused by faulty ignition system components. Plugs are likely okay, but I suspect that you may have some bad plug wires.

Customer: replied 1 year ago.
what about coil not puttin enough juice out under load starts it but weak coil i heard could do this the amps have to be a certain range that was never replaced
Expert:  Dave Nova replied 1 year ago.

Yes a failing coil can cause the same symptoms.

Customer: replied 1 year ago.
Can you believe my luck that is a brand new jasper motor with about 30,000 on if that and the cam lobes are wore chevy dealer found it and the 3 yrs is past by about a yr for warranty gonna cost me around 2500 to fix must have got a cam machined a bit wrong they had the valve covers off and seen that the lifters are not in sync
Expert:  Dave Nova replied 1 year ago.

That is an odd one for sure. Not something that would be expected. We did see a lot of camshaft failures in the 1980's on GM V8 engines, but it is not common today. Glad you were able to get it sorted out, sorry that it is going to be an expensive fix.