99 i30 key on engine off clicking from transmission?

[skipper6567]

The car drives fine, idles very rough but not erratic. the rpm up and down is constant,what i mean is its the same rate up and down up and down...cleaned all plenum,tb,iac,egr,map,bro,swirl valve,hard to start without a little pedal push,Surges when in gear because engine is up and down,transmission seems to work perfect,get this strange ticking that i can actually feel through the transmission pan? also whith key on and engine off i can hear a noise when i move the throttle,that noise seems to come from the front lower part of the engine compartment,I had erratic voltage with key on ,no run at the tps connector?No vacum leaks, When I first start engine it goes to 1200 or so rpm then in 5 seconds drops to 550 650 and just hunts up and down,even with accesories on,no matter. no codes,had egr insuficient code that started this mess.i took egr off and apart,cleaned..I also have replaced almost every sensor ,i went to the j/yard and ripped 4 infiniti cars apart,all coils,plugs chnaged, seems like the engine is on and off and on and off,like 1/2 cylinders fireing but very consistent with the up and down on the tach?? i'm pretty good with a wrench and multimeter,just running out of things to replace or check??Thanks

[Q451990]

Do you have the factory service manual? If not it's available at www.nicoclub.com/FSM/

I don't have a lot of I30 experience, but if you haven't read the FSM it might give you some new ideas.

Heath