1990 240sx coupe power problems

[NismoIncRacing]

if ne1 can help here it would very helpful i have taken my car to 3 differant shops and they couldn't figure out the problem this is what happens..... my engines shakes badly, back fires, digital gauge cluster doesnt work all the time, bucks while driving, and the battery doesnt stay charged... this is what ive done so far ive changed the whole ignition system, full tune up and have had the charging system check everything come back normal.. now when i drive it i heard a buzzing sound coming from the dash then the battery and break light comes on thats when my car starts bucking and i cant take it past 3000 rpms but this only happens once in awhile if ne1 has had this problem or can tell me what is actualy wrong plz let me know

[180fan]

1. have you checked the fuel injectors to see if that's what's causing the engine to buck around the engine bay?2. digital cluster not working, have you checked for loose plugs on the back of it?3. battery not staying charged = bad alternator. that brake and battery light coming on tells me it's your alternator without a doubt.

can't take it past 3k, it could be your mafs or your tps. I suspect your tps first though.

[rogoman]

All the problems could be tied to one or more bad ground connections.

[NismoIncRacing]

injectors are fine i have venom injectors and fuelrail, alt is fine its the voltage regulator thatz bad buschings are shot to ****. and for the cluster i tore the dash and checked and cleaned all the plugs.....but the main problem i really had was a bad power stearing pump so i took it off car is a lot quicker now

[benemorius]

So... are all the problems fixed or....?

[NismoIncRacing]

to an extant there fixed i still had low end power problem but i found that was caused from a worn out clutch so far everthing better just waitin to get that motor drivin fan out and pput in the eletronic powered one and rip out my ac and all that goes with that