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 350matt Your Own Question
350matt
350matt, Engineer
Category: Mazda
Satisfied Customers: 20611
Experience:  Mechanical Engineer BEng Hons22 years experience
12772297
Type Your Mazda Question Here...
350matt is online now
A new question is answered every 9 seconds

Car shuddering and hesitating when speed reaching 30 _ 45

Customer Question

Car shuddering and hesitating when speed reaching 30 _ 45 mph and l feel loss power. . it is mazda cx9 2008 model
JA: Are you fixing your CX-9 yourself? What have you tried so far?
Customer: some mechanic told that it is malfunctioning torque converter but other one told transfer case
JA: Do you have the torque specs?
Customer: no I don't have
JA: Anything else you want the mechanic to know before I connect you?
Customer: l need to know what are the main symptoms of bad torque converter orTc
Submitted: 1 month ago.
Category: Mazda
Expert:  350matt replied 1 month ago.

hello

its possibly transmission related so I'd 1st check that the fluid level is correct and that it not black and smelling 'burnt'

if thats OK then

This sounds like a lack of fuel and could be a lack of fuel pressure from the electrical pump at the tank.

1st thing to try is to remove the fuel filler cap and then flick the ignition on whilst listening for the brief ‘buzz’ of the pump

If the connections to the pump are corroded or damaged then the pump could stop at any time or could not be running at full speed. Check that its relay switches in and out and the relay contacts are clean and bright – replace the relay if in any doubt and do the same for the fuse,

Ideally measure the pressure at the injector rail (should usually be around 3Bar / 45psi +) and if this is low check the pump as described and also consider changing the fuel filter as if this partially blocked this too will reduce pressure.

You can also get this issue with contaminated fuel , if there’s water or dirt in the tank then either the petrol floats on top of the water or the filter sock on the pump is choked up – so if the other things check out then I’d consider pulling out the fuel pump and cleaning the filter sock

And one other thing to try is to loosen off the fuel filler cap, as there’s a 1 way valve built into the cap to let air into the tank and so prevent a vacuum from being created as the fuel leaves the tank to the engine

If this helps then replace the cap with a new item

Expert:  350matt replied 1 month ago.

Hi

do you still need help?

Bear in mind that the site takes a deposit from you at the beginning and this is held by the site until you rate my answer at which point the cash is split between the site and the expert. I am only paid for my work on this question if you rate my answer, using the star system at the top of the screen. Please do not forget! Thank you

Related Mazda Questions