Break down :(

[BMCC]

Car misfired badly yesterday and I had no power, had to pull over on the worst road possible if you are from my neck of the woods. M8 motorway just after the Kingston bridge. Really busy road, just glad I didn't stop on bridge or just before as it would have been very dangerous.

I was towed to a nissan garage who said today they couldn't get the car to misfire so can't diagnose the problem. They say they got the car hot then took it for a spin with no misfire twice. Problem occurs for me when hot and on light throttle around 2k-3k rpm. Car seems to get into a rut of misfires then clears eventually.

This has been a problem for a number of months and I have changed the following:

Spark plugs
ignition leads
rotor arm
rotor cap
ignition coil
fuel pump
fuel filter
various vac hoses
Air filter cleaned

nissan datascan says
tps: 0.5v at idle
air flow metet at idle: 1.18v

All new parts, always run on super unleaded. Not sure where to go from here. The problems intermittent but I don't drive the car everyday maybe 1 or 2 a week. Some times cars OK other times it will misfire but you can drive through it. Couldn't do this on m8 as everytime I touched the pedal it misfired. All I could do was keep the revs up and hope the traffic kept going.

 

[PobodY]

Boost/vacuum leak when the hoses are warm?
Has anything else been done; are you running on a standard map?
Which plugs have you put back in? - I found the precious metal tips foul really easily and have not looked back after switching to copper cores.

 

[BMCC]

could be a vac leak but not from any hoses I can get at. standard car, copper core plugs heat range 7 (bkr7e)

 

[Fast Guy]

Vac leak or maybe something like a worn wire/connector that's playing up when warm.

For years I had an intermittent misfire on my montego turbo and it was a pig to drive when it happened and I could never find it. Years later it suddenly got permanent for a while, so I pulled over, popped the bonnet and started grabbing handfuls of wiring loom and moving it to see if anything happened. Bingo! got near the crank sensor and it cleared. Turned out in this case the two wires going into the sensor were fucked, one was broke so making an intermittent contact, the other one was holding on by one strand of wire.

Have you done a fault code check?

 

[campbellju]

Dodgy earths or ignition amp are other areas to rule out

 

[BMCC]

Fault code showed MAF but don't bring on engine check light for some reason. I've swapped out the MAF with help from Scott @ Warpspeed and cleaned up as many earths as looks possible. Fault stays off and no misfiring but I need to run the car for a good few journey's before I say this one is solved. Fingers crossed.