I HAVE A 2001 ALERO 2.4L TWIN CAM. I AM HAVING ROUGH IDLE PROBLEMS. HERE IS A LIST OF THINGS I HAVE ALREADY DONE. CHANGED IGNITION HOUSING,CHANGED BOOTS, CHANGED SPARK PLUGS AND IGNITION COILS.WAS GETTING A P0302 CODE(NO.2 CYLINDER MISFIRE. SWAPPED THE INJECTORS IN 1&2. NOW IM GETTING A PO3OO CODE( RANDOM MISFIRE). CAR RUNS SMOOTH AT HIGHER RPMS, BUT VERY SLUGGISH AT IDLE. PLEASE HELP.......RUNNING OUT OF PATIENCE. ALSO CHANCED THE INJECTORS BACK, STILL GETTING P0300 CODE.
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Yes, i'm still waiting on an answer to my problem.......PLEASE HELP.
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Hello and Welcome to Just Answer. My name is XXXXX XXXXX X will try my best to assist you and your 100% satisfaction is my goal. I have been working on these vehicles for over 10 years so I am very familiar with this system and how they work. However, keep in mind, that I need some solid concrete facts/evidence/clues from you in order to give you a good answer about your vehicle. Please realize that all my answers are based solely on the info that you provide me with.I would check the fuel pressure regulator. It is located on the fuel rail. It is round, about a quarter size and has a vacuum line going to it. If the regulator is leaking gas than it can cause this problem. Pull off the vacuum line that goes to the regulator. Be absolutely sure there is no gas in the vacuum line. If there is, the diaphragm has ruptured and there is gas entering the engine that is not accounted for and the regulator will need to be replaced! If the regulator checks out ok, then you might have an air or a vacuum leak. This is very common! Open the hood and listen for a hissing sound when the engine is running. Unmetered air can enter the engine through a vacuum leak, a dirty airflow sensor that is not reading airflow accurately, an EGR valve is not closing and is leaking exhaust into the intake manifold, an EGR valve that is allowing too much flow.If it is hard to pinpoint take some brake cleaner or starting fluid around the intake manifold and vacuum lines and see if the engine stumbles or if the idle is affected. Be extremely careful when doing this!Also, your throttle body may be carboned up and need to be cleaned! This can cause all sorts of idle and hesitation problems. This is caused by the throttle plate not seating properly. The First thing i would do is clean out the throttle body with some throttle plate and intake cleaner and a small brush. Another common cause would be the Idle Air Control motor. This is very common on older cars. The IAC motor gets lazy and cant keep up with the fast idle changes. Also when the IAC motor is out, I rec to check the passages for carbon build up. If they are plugged they need to be cleaned out. Possible Causes Check for air leaks in the Air Induction system (e.g., in the intake manifold)Check for air leaks in the PCV system and in its related hoses and/or valveIdle air inlet passage or throttle bore is dirty or full of depositsIAC valve has failed MAF sensor is dirty, "skewed" or installed improperlyThrottle plate, throttle shaft or linkage is damaged or stickingTP sensor is out-of-range or "skewed" high
I hear a leak at the exhuast man. i changed the gasket there already and also the cam shaft housing gaskets. could the exh. man become warped or even cracked over time because it is plastic.
Hello!The answer would be yes.. it sure can. However, this usually does not cause an idle issue.
but wouldnt it cause an air vacuum leak, that would cause erractic idle. i changed it and the cam cover gaskets because of high idle. that is solved now there is rough idle ....which was also the case before when rpms would drop to normal.
This is an air leak.. but not a vacuum leak. Only air and vacuum leaks going into the engine will cause an idle issue. Not an exhaust leak
but the man. bolts up to the engine. the man that the throttle body sits on. maybe thats not the correct name of it .
If your talking about the intake manifold.. then yes.. but no.. not the exhaust manifold.
yes thats what it is the intake manifold. could that be the culprit? maybe its warped and wont seal correctly. or maybe theres a hairline crack in it thats hard to notice with the eye. is there a way to check it ,or should it just be replaced?
If it is cracked, yes.. it needs to be replaced. Hands down. If the gasket is leaking in between the manifold and the cylinder head, the gasket needs to be replaced.
i already changed the gasket. i'll take it back off for a better inspection. thanks buddy, i think were on to somthing. do you recomend gasket sealer or no?
Generally speaking.. no. I do not. What ever is leaking vacuum, it needs to be replaced. If the manifold is not sealing correctly even with a new gasket it could just be warped.. which again.. it would need to be replaced.I hope this helps! Please don't forget hit the green accept button so that I may get credit for the time that I have spent with you. This is necessary for me to be paid for my work and get credit for assisting you. Your question will not close, and you will still have the opportunity to follow-up if needed. Leaving a bonus and positive feedback is not required, but doing so is certainly appreciated!I do hope you are as honest with me about your vehicle as I have been with you. If you have any further questions or if you need more assistance, just hit the reply button and we can continue our conversation. Please remember, even if you accept my answer now, you can still reply or respond back to this thread at any time you wish at no further cost to you. In addition, please allow time between answers as I may be off line spending time with my family or assisting other customers. You can always request me by using the link through my profile page. Just Click on "AMEDEE" next to my picture and I will be sure to respond back in a timely manner. Thanks in advance!Best RegardsAMEDEE