Question about 2004 Infiniti QX4
(1999 QX4) (No "SERVICE ENGINE" light) The symptom started out as rough to start. It acted like it was starved of fuel. The fuel pump and fuel filter was replaced as well as dist. rotor and cap. Truck ran great for a day. Then it started stalling when accelerating the engine past 1/2 throttle only when it was warm. Now, it does it cold. When it stalls, I can tell it is backfiring because there are exhaust fumes in the intake after a stall. I even re-checked the plug wire routing. All is good. At idle, you can see the tachometer slightly flicker, but it is hard to feel. The fuel filter was replaced again. The fuel was checked for water. The fuel pump lines were inspected. The exhaust smells a little rich. This might just be my imagination, though. I'm drawing a blank and feel a sensor is going out or already has. There is still no engine light. I'm confused and am close to taking it to the dealership. Your suggestions are greatly appreciated.
Check to see if your spark plug wires are not cracked or worn. They would make the engine run rough when cold or damp more often then when the engine drys up when warmed up- just an easy thing to check...
Posted on May 24, 2009
SOURCE: I have an 1999 Infinity
Have your fuel pump pressure tested!
Your car could be running great because its demand for fuel pressure is met at idle. But at part and wide open throttle you fuel pump could be running aground.
A mechanic with a fuel pressure gauge can drive the car around and see if the pressure falls flat during off idle throttling.
Good luck and be careful!
Posted on Mar 19, 2010
SOURCE: 1998 Infinity Q45
Hi, i would replace the air filter, make sure the air hose from the air filter to the intake is not kinked or blocked and check for vacuum leaks. If these are all fine, I would check the fuel pressure as it is possible the pump is weak and not supplying enough fuel.
Posted on Nov 18, 2010
First of all you need to access the Engine Control Module (ECM) using suitable diagnostic equipment connected to the data link connector of the car, in order to pull out all DTC's memored. DTC = Diagnostic Trouble Code. Then you will bu full informed about the root cause of the problem, and you will be able to repair & replace bad pieces and reset the ECM.
Let me know please about found DTC's. I will assist you kindly to fix the problem.
Posted on Sep 05, 2011
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How to Check? The MAP has three electrical
pins, one for 12 volts (or 5 volts) reference, one for ground and the third
(the middle one generally) is the 'signal' output. Put a voltmeter positive connector on the 'signal'
pin of the connected socket (back probe by inserting a bit of wire). Apply suction to the vacuum input, even
sucking on it with your mouth, should result in a measurable voltage output. At normal air pressure (open throttle) the
voltage seen should be 0 volts. As
vacuum is applied the voltage output should change to about 5 volts (throttle
closed at idle). If no transition seen
the MAP is faulty.
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