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 Tim's Auto Repair Your Own Question
Tim's Auto Repair
Tim's Auto Repair, mechanic
Category: Chevy
Satisfied Customers: 15969
Experience:  Have owned a repair shop for 25 yrs.
Type Your Chevy Question Here...
Tim's Auto Repair is online now
A new question is answered every 9 seconds foot..brake pedal and my engine is making weird noises

Customer Question

my car is jerking forward when i have my foot on the brake pedal and my engine is making weird noises. But when i turn the air or heat on it doens't do it. Can someone tell me what this could be b/c i need to prepare for a big shop bill
Submitted: 7 years ago.
Category: Chevy
Expert:  Tim's Auto Repair replied 7 years ago.
please explain..does the idle go up and down?
Customer: replied 7 years ago.

i dont remember. im not the one that mainly drives my car but i was just made aware of the problem friday. It seems to have got worse since I first knew about it a few months ago.

Expert:  Tim's Auto Repair replied 7 years ago.


check it out,and let me know what it is doing...also if the engine light is on,please get me the codes


Customer: replied 7 years ago.
This is what is going on. When im driving my car and i am stepping on the gas to make the car speed up, it gets to a certain speed and starts to jerk and hesitate or whatever its called. Then after i let my foot off the gas and then step on it again it stops. But when i first start my car up and it is still in park, my car engine makes some weird noises and is rocking back and forth like it is just gonna stop running soon and that is my concern because i dont have money to just go buy cars here and there nor to pay outrageous shop bills. Also, on my car i had a broke pcv valve and i had to find a way to fix it so i have a little tube that goes over where the tubing was on my pcv valve because the ones from my job dont come with the black tubing on them. When i had to send my car to the shop last time i paid seven hundred and something dollars to pay for my battery, serpentine belt, belt tensioner, alternator and i believe thats it. The engine light was on then but it is not on now. There are no lights that come on my dashboard and no kind of warning sounds when im driving that a light is on. When i got a tune up after i had this work done, i had everything changed like the spark plugs and wires and all that but my pcv valve problem i still haven't got fixed and i never got my fuel filter changed since i had the car. So i dont know what to do and im just sitting here trying to figure out where to go from here as painless as possible. I know im gonna have to spend some money but i would like to get a pretty good idea of whats going on before i go from there if possible.
Expert:  Tim's Auto Repair replied 7 years ago.


this does sound like a fuel problem...sense you have no engine light on...the first thing you need to do is to test the fuel presure..these must have no less then 41psi at anytime.....your fuel filter may be clogged,so you may want to change this first...also it is posable to have a bad fuel presure regulator....checking the presure is your next step..print the info below



please ACCEPT my answer so I can get credit for my work.i don't receive commission unless you do ..i'm not always going to be giving you good news,so please dont let this stand in the way of you accepting my does not cost you more money.we will still be able to communicate.. Bonuses and positive feedback are appreciated!if you are not satisfied with my answer,please do not leave bad feed back,i will gladly opt out and let another expert handle the question.PLEASE ASK IF YOU NEED MORE HELP

Service and Repair


  1. Negative battery cable.
  2. Relieve fuel system pressure.
  3. Raise vehicle on hoist.
  4. Quick-connect fitting.
  5. Fuel feed pipe nut from fuel filter. Drain any remaining fuel into an approved container.
  6. Slide fuel filter Out of bracket. Inspect Fuel pipe 0-ring for cuts, nicks, swelling or distortion. Replace if necessary.


WARNING: To Reduce the Risk of Fire and Personal Injury: If nylon pipe is nicked, scratched or damaged during installation, it must be replaced .

  1. New plastic connector retainer on filter inlet.
    • Install in same position as on old filter.
  1. Slide fuel filter into bracket.
  2. Quick-connect fitting.
  3. Fuel feed pipe nut to outlet side of filter. Tighten Use backup wrench to prevent filter from turning and tighten fuel filter outlet nut to 30 Nm (22 lb. ft.) .
  4. Lower vehicle.
  5. Tighten fuel filler cap.
  6. Negative battery cable.

Turn ignition switch to "ON," position for two seconds, then turn to "OFF" for ten seconds. Again turn to "ON" position, and check for fuel leaks.

Diagnostic Charts


Chart Fuel System Diagnosis
Chart Fuel System Diagnosis
Fuel Pressure Check Hook-ups

When the ignition switch is turned "ON," the Powertrain Control Module (PCM) will turn "ON" the in-tank fuel pump. It will remain "ON" as long as the engine is cranking or running, and the PCM is receiving reference pulses. If there are no reference pulses, the PCM will shut "OFF" the fuel pump within 2 seconds after ignition "ON" or engine stops.

An electric fuel pump, attached to the fuel sender assembly (inside the fuel tank), supplies fuel through an in-line filter to the fuel rail assembly. The pump is designed to provide sufficient fuel flow for all engine demands. A pressure regulator attached to the fuel rail, keeps fuel available to the injectors at a regulated pressure. Unused fuel is returned to the fuel tank by a separate line.

Number(s) below refer to circled number(s) on the diagnostic chart.


  1. Connect fuel pressure gage as shown in illustration. Wrap a shop towel around the fuel pressure connection to absorb any small amount of fuel leakage that may occur when installing the gage. With ignition "ON" and fuel pump running, pressure should be 284-325 kPa (41-47 psi). This pressure is controlled by spring pressure within the regulator assembly.
  2. When the engine is idling, manifold pressure is low (high vacuum) and is applied to the pressure regulator diaphragm. Vacuum will offset spring pressure and result in lower fuel pressure. Fuel pressure at idle will vary somewhat depending on barometric pressure but, should be less than pressure noted in Step (1).
  3. A system that does not hold pressure is caused by one of the following:
    • Leaking fuel pump check ball.
    • Leaking fuel pulse dampener.
    • Leaking valve / seat within pressure regulator.
    • Leaking injectors(s).
  1. A leaking injector can best be determined by checking for a fouled or saturated spark plug(s). If a leaking injector can not be determined by a fouled or saturated spark plug, the following procedure should be used:
    • Remove intake plenum.
    • Remove fuel rail but leave fuel lines connected.
    • Lift fuel rail out just enough to leave injector nozzles in the ports.

WARNING: To reduce the risk of fire and personal injury that may result from fuel spray on the engine, make sure fuel rail is positioned over injector ports and injector retaining clips are intact.

  • Pressurize the fuel system and observe injector nozzles.
  1. Fuel pressure that drops off during acceleration, cruise or hard cornering may cause a lean condition and result in a loss of power, surging or misfire. This condition can be diagnosed using a Tech 1 scan tool. If the fuel system is very lean, the Oxygen Sensor (O2S) will stop toggling and output voltage will drop below 500 mV. Also, injector pulse width will increase. NOTE: Make sure system is not operating at "Fuel-Cutoff" which may cause false readings on the scan tool.
  2. Fuel pressure below 284 kPa (41 psi) may cause a lean condition and may set a Diagnostic Trouble Code (DTC) 44. Driveability conditions can include hard starting cold, hesitation, poor driveability, lack of power, surging or misfire.
  3. Restricting fuel flow in the fuel return line as directed causes fuel pressure to build above regulated pressure. With battery voltage applied to the pump "test" connector, pressure should rise above 325 kPa (47 psi) as the valve in the return line is partially closed. NOTE: Do not allow pressure to exceed 414 kPa (60 psi) as damage to the regulator may result.
  4. Fuel pressureabove 325 kPa (47 psi) may cause a rich condition and may set a DTC 45. A driveability condition can include hard starting (followed by black smoke) and a strong sulphur smell in the exhaust.
  5. This test determines if the high fuel pressure is due to a restricted fuel return line or a faulty fuel pressure regulator.
  6. The pressure regulator filter screen is designed to trap any contaminants introduced during engine assembly. If dirty, it can be removed with a small pick and discarded without potential harm to the regulator.
Service and Repair


Fuel Rail Assembly



  1. Negative battery cable.
  2. Relieve fuel system pressure.
    • Refer to Fuel System / Service and Repair .
  1. Intake manifold plenum.
    • Refer to Intake Air Plenum.
  1. Vacuum line to regulator.
  2. Fuel pressure regulator attaching screw.
  3. Place towel under regulator to catch any fuel, then remove pressure regulator from fuel rail.
    • Twist back and forth while pulling from rail.
  1. Retainer and spacer bracket from rail and discard.
  2. Fuel pressure regulator from engine fuel return pipe.
  3. Pressure regulator inlet 0-ring and discard.

Filter screen for contamination. If contaminated, remove and discard filter screen.


  1. Lubricate new pressure regulator inlet 0-ring with clean engine oil and install on regulator inlet. CAUTION: The fuel return pipe must be connected before tightening the regulator attaching screw to prevent the regulator from rotating. Rotation of regulator could damage retainer and spacer bracket and lead to fuel leak at regulator inlet.
  2. Fuel return pipe to regulator.
  3. New retainer and spacer bracket into slot on fuel rail
  4. Pressure regulator to fuel rail. Tighten Engine fuel return pipe nut to 7 Nm (13 lb. ft.) .
  5. Pressure regulator attaching screw.
  6. Vacuum line to regulator. Tighten Pressure regulator attaching screw to 8.5 Nm (6 lb. ft.) . Inspect Verify that retainer and spacer bracket is engaged in slots in fuel rail. Grasp and pull on regulator to ensure that it is properly seated. Turn ignition to "ON" for two seconds and then turn "OFF" for 10 seconds. Once again turn the ignition to "ON" and check for fuel leaks.
  7. Intake manifold plenum.