1993 Nissan Quest problem with erratic engine behaviour...help!!!!!!!!!!!!!!!!!!

[jc179]

Hi All,

Have a 1993 villager with ~160k. The problem is after the engine warms up, it starts to miss badly, shake and rattle. Whats odd about it, even when its warm, if you downshift to a low gear and push it to the floor a few times, it will stop this behavior and return to normal. I can turn the vehicle on and off and it will start up and run normally.

This problem has been going on for about a year now and I have had to two different garages and the problem has not been able to be fixed!

So far it has new wires, plugs, cap, rotor. The IAC and TB were cleaned, maf, and tps sensor test OK. I do not get any Check engine light either. I have tried pulling the flash codes from the cel, but that turned up once fuel mixture or mis fire, but have not seen the code since the wires were done.

A friend suggested that when it warms up, it could be the coil. I have changed that with a used one to no avail, the problem remains, but seems to be slightly less (maybe - need more testing still).

I'm still not getting any closer and need some expert help!

Thanks for any advice

[driftingmy240sx]

has the fuel system been checked?

[jc179]

No... but I would think if there was a fuel pressure problem, running WOT would starve the engine? Or are you thinking something else i'm not ?

Let me know what you have for ideas!

thanks!

[driftingmy240sx]

the fuel trim could be off due to vacuum leaks or you could have injectors that are leaking due to poor pintle seating.