QuestionQUESTION: I have a 99 Nissan max. Problem i took it in the shop for was hesitation at 1500-2100 rpms. And sometimes acting like it could stall at a red light. They sold me fuel injector cleaning, fuel filter, oil change and throttle body cleaning and an oxygen sensor which was tripping the ck engine light. Got the car back it was revin to 2100-3000 rpms when cold on a start up. Took it back to them and now they say they never should have done the throttle body cleaning and that it needs an idle air control motor and they they are replacing it for free. Took it home tonight b/c the part isn't in till monday and i noticed that the gas pedal is not compressing when you are at 0 rpms looking to accelerate from any stopped position, it will go if you jam on it. Looked at the cables that accelerate the car and notice that when you accelerate the car one cable moves and one does not ..what does this mean? Is it expensive?
ANSWER: Stephanie,
One cable is for the throttle and the other for the cruise control. So, it is not a problem with one moving. The idle air control valve (motor) is a common problem on Nissan cars and after a good throttle cleaning trash probably got stuck in it and that is causing the high idle. Now, for the original problem of stalling at lights. I would almost bet the mass airflow sensor is the cause. But, let them get the idle air control valve replaced and see if you have an idle problem. If you do have them do a test of the mass airflow sensor. Problem is that it usually never sets the check engine light and unless they are really Nissan technicians they would not know to look for this. Nothing would point a normal mechanic to the mass ariflow sensor unless they know to look for it.
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QUESTION: Hi, thanks for the information. I got the car back after the Idle air control motor was replaced and the store manager said that he cleaned the throttle plate to address the sticking of the gas pedal... which he said was due to a burr being in there? Does this sound about right? This seems to have helped a bit although the pedal is still sticking slightly intermittently. The revving of the idle is still there however and really seems worse now than before. It is an issue on a cold or very cold start. It is now actually idling at 2100+ RPM, then dropping to 1500 rpm's then idling back up to 2100 rpm..than dropping again to 1500 and it goes up and down until the car is warm about a 4-5 min warm up. Once the car is warmed up, every now and again it will idle at about 1000-1100 rpm at a red light. I am actually taking it back to the repair shop in the morning & the repair shop manager said that he will take it to Nissan to have them diagnose what the problem is. I did not have any of this idling issue before I took it in to have it checked or before they did the throttle body cleaning. Is this type of thing typical? Or something that happens when this cleaning gets done? Also is a mass airflow sensor expensive? Do you think that if the mass airflow sensor is bad, that it would have caused the hesitation that I was originally experiencing? I really appreciate the information. It is difficult to ascertain what is the honest answer when you get so many different answers about what is what under the hood.
ANSWER: Stephanie,
A burr in the throttle bore is common and that would account for them claening the throttle body. The idle jumping, as you describe it is not normal and could be a sticking idle air control valve, if there is debris in the tract or the pintle valve is not seating properly with the idle air control valve. So, let's see what Nissan has to say. A mass airflow sensor could be the culpret but it is usually associated with low idle and not a high idle. So, I still would think the throttle body, idle air control valve or a vacuum leak that the computer is compensating for. Email me back and let me know what you find. It sounds like the shop you are using is honest and attempting to correct the problem. Oh, a mass airflow sensor for your car is about $200 bucks. Check out rockauto.com or courtesynissan.com for prices. Much cheaper than the dealer... And, easy to install. You just need a screwdriver and you could do this one yourself. If you want to email me back and I will walk you through the procedure. You won't even get dirty and the part is right up front, by the air filter.
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QUESTION: Hi, so I took the car back to them today and the manager of the store took the car to Nissan for diagnosing. Nissan more or less gave him a hard time and did not want to wait for the car to get cold to see the idle issue and said they thought it was still the idle air control valve that was causing the issue. So that was replaced for the 2nd time and he thinks the idling problem is solved, I will not know until it gets cold. I picked it up and drove it tonight and there is still the sticking in the gas pedal upon acceleration. I am thinking of taking it to another mechanic for a 2nd opinion because I want to really be sure its safe to drive. Are the burr's that you are referencing difficult to clean/ hard to get to once they occur?
AnswerStephanie,
Well, lets hope the idle problem is corrected. If not, take it to anther shop for diagnosis. The sticking of the throttle should be addressed and should be quite easy. If the problem is with the throttle body and the shaft is not worn. Nissans usually do not have this problem. This could be solved by cleaning and lubricating the throttle shaft and return spring. If it is the throttle cable it is just a matter of adjustment and if the internals are worn it is just a matter of thr throttle cable being replaced. Have them check this as a sticking throttle is not good. Now, I do not want to appear dumb here. But, the floor mat is not bunching up at the throttle is it? I have had that happen on a number of cars lately. The floor mat catches the pedal and you get momentary sticking. Well, it has happened to me...
