2001 3.0 L Rough Idle nearly stalls
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2001 3.0 L Rough Idle nearly stalls
I am a former Nissan tech. trying to diagnose a rough idle issue for my mother. Consequently I don't know jack***t about Jags.
The car idles very rough once it warms to normal operating temp. If I disconnect the mass airflow sensor the idle picks up to between 1000-1100 rpm and then settles around the 750-800 rpm range and the idle is much smoother, I assume this is because after the disconnection of the mass airflow the ECM starts pushing 100% fuel trim. If it weren't for this condition I would speculate that there were bad coil packs or a vacuum leak or maybe even something more sinister. It had stored codes of P0171, P0174, P1131 and P1151. Just for kicks I threw a mass airflow sensor at it with no success. Before I start hurling parts at this thing some more I would appreciate any and all suggestions. Please excuse my newbness. Thanks
The car idles very rough once it warms to normal operating temp. If I disconnect the mass airflow sensor the idle picks up to between 1000-1100 rpm and then settles around the 750-800 rpm range and the idle is much smoother, I assume this is because after the disconnection of the mass airflow the ECM starts pushing 100% fuel trim. If it weren't for this condition I would speculate that there were bad coil packs or a vacuum leak or maybe even something more sinister. It had stored codes of P0171, P0174, P1131 and P1151. Just for kicks I threw a mass airflow sensor at it with no success. Before I start hurling parts at this thing some more I would appreciate any and all suggestions. Please excuse my newbness. Thanks
Last edited by farquand; Dec 14, 2009 at 05:50 PM.
Lower breather elbow below the fuel injection rail assembly. Remove intake, fuel injeCtor rail assembly and its under there towards the back. About a 5/8" 90* rubber elbow, itll be the one with the hole in the side of it leaking vacuum. replace the straight rubber piece connected to the metal pipe on the other end of the 90* elbow....
Like my supercharged 400+hp Nissan Frontier in my sig..cams, forged pistons, billet rods, ported heads, headers, hi flo exhaust and 10psi boost from a 4.0V6
Like my supercharged 400+hp Nissan Frontier in my sig..cams, forged pistons, billet rods, ported heads, headers, hi flo exhaust and 10psi boost from a 4.0V6
Last edited by Brutal; Dec 15, 2009 at 01:54 PM.
if theyre the individual orings 6 each upper and lower NO, but if theyre integral 2 upper and 2 lower then replace those. Those suck and distort easily creating vacuum leaks when reused(oil vapor destroys them just like the vapor hoses). The large individual are better and stand up to many reuses. but they were changed mid model year in 02 (different intake and injection rail assembly
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Perfect diagnosis. The elbow was collapsed and had a big hole in it. On another note, when I was removing the intake plenum the bolts were so tight that when I was loosening them, with a 1/4 drive ratchet mind you, 4 of them stripped out of what I guess is called the injector riser. I put a little heat on the 4 bolts with the brass insert still attached to remove the threaded brass insert from the bolt and epoxied the inserts back into the riser using some JB Weld. I am letting that cure and will reassemble in the morning. Do you think this will work? Will the epoxy hold the torque and speaking of which what are the torque specs for those plenum bolts?
Thank you for the advice, it made the task infinitely easier.
Thank you for the advice, it made the task infinitely easier.
Last edited by farquand; Dec 17, 2009 at 08:44 PM.
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