Nissan Maxima V6 intermitant engine fault

I received this 1994 car from a friend, it is an automatic, and everything works but it has developed a problem. At first it was just uneven idling with jerks and hesitancy as it warmed up followed by intermittent jerking when hot. A local garage checked the flash codes and there is nothing showing up. I was fairly certain it was all cylinders or one bank failing for a few revs but changed the ignition leads, distributor cap and rotor arm just in case.

The problem is still there and in this cold weather the car occasionally stalls when pulling up to junctions after a 2nd cold start. This is a bit awkward with an auto as you lose steering and brake power assist with no overrun to help out, so my daughter who is the main driver is wary or using it..

I just need an idea as to what else to check. The fact that it starts and runs faultlessly for the first start each day may be significant. The problem always seems worse after a warm or second start. This makes me wonder if there is a fault either in a temperature sensor or its wiring to the ECU, except I don't know where to look as the only manual or diagrams I have is from a 2000 model.

Also the engine runs cool on the temp sensor and the heating is poor, yet under bonnet everything seems hot enough. I wonder if a faulty thermostat could fool the ecu?

AJH

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AJH
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Your first problem sounds like either a faulty main relay jumping in and out, OR a bad connection at, OR a faulty ignition amplifier (called an Ignitor on jap cars) all of which would give you intermittent but violent loss of power.

Does the rev counter plumet with the loss of power, or does it continue to read the dying engine revs? If the former, then its definately loss of power to the ECU or ignition primary problems.

Your low running temp is more than likely a lazy 'stat. Change it. Not connected to the first problem-though you may find the engine running hotter will agrivate the spluttering. If so then i'd change the amplifer straight away. Some freeze spray may help here to double check.

Tim..

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Tim..

The car's not here but I will try and check this, from memory it shows the loss of revs but does not fall back to the stop. At speed of course the transient loss of power is too short for much to register, other than a jerk.

What does the freeze spray do?

DO you know where this ignition amplifier is on this car?

Thanks for your input.

AJH

Reply to
AJH

Breif intermittent problems like this are very hard to trace, especially at a distance! Is there any pattern to it- going around corners, or bumps etc? I think I would start with a wiggle test and go from there.

Very very handy for tracking temperature related fauts with sensors and the like. 99% of the time they go u/s when hot, so if a blast with the spray brings the car back to life you're doubly sure you have found the problem.

Base of the distrubutor as far as i recall- though i may be confusing your V6 with the Mazda Xedos /Ford Probe V6 which are very simialr!

Tim..

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Tim (remove obvious)

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