I just bought a 1991 Nissan Maxima V6 3.0L (VG30E) automatic at a charity auction and it's had this problem ever since. When I can get it to start, it idles very low and when I step on the accelerator, almost nothing happens....the tach just twitches a little. Same story when I move the throttle under the hood by hand, so its not the cable.
I get a code 55 from the ECU diagnostics mode 3 (code 55 = normal operation). I've done all the ECCS sensor checks in the Haynes manual and everything passes (though I know that doesn't mean they're really working properly since the checks are so limited).
The distributor was worn out so I replaced it and I'm getting a good spark. I checked the compression - its within range and the same in all six cylinders. The fuel pump is ok, I replaced the fuel filter, plugs, and the throttle valve switch, but still have the same problem.
**This is interesting - changing diagnostic modes on the ECU by turningthe screw caused the idle to normalize and allowed me to rev the engine
with the accelerator for about 20 seconds. I could only make this happen 2 times while the engine was idling. Similarly, I changed the modes without the engine running (just had the key at "ON") and my buddy said he heard the injectors click.**
So I'm guessing one of the sensors is causing the ECU to not send power
to the injectors....or the ECU is no good. How can I find out what's going on?? Tomorrow I'm going to check all the grounds and clean all the connectors. Any other ideas or guidance? Please help.