4agze misfiring under light load

[Tom86]

Hi everyone,

My 4agze in the ae86 recently start to misfire, but only under light load e.g cruising along at 80kph 2500rpm when I gradually press the throttle to go a bit faster you can feel the engine stumble a bit around 3-3.5krpm. Doesn't happend if I just floored it or press the throttle hard. The car still making good power drives fine just pop and stumble around the 3000-3500rpm range. You can also hear the misfire if you gradually rev the engine at idle .

So far I've changed the spark plugs, ignition leads, coil packs, new O2 sensor and had the injectors sonic cleaned. After all that the problem is still there. Not sure what to do next any suggestions?

Thanks

Tom

[forey]

Put a multimeter on your tps signal and ground wires to make sure it has correct voltage
If not then adjust it, between 0.6v and 0.7v at idle as far as i know

If i has an airflow meter carefully clean that out too

[punkture]

Map or afm?

[zahmad]

Good start with the basics taken care off...
Second that on the AFM...

[Tom86]

MAP sensor 4agze from AE92 Levin.

[maj]

Check your MAP sensor.

There's been quite a few similar issues pop up on this forum recently, exactly the same kind of issue with a misfire on light throttle but not so bad at WOT, also occasionally bad idle. MAP sensor replaced and all was well.