Why does the rpm & speedometer needle bounce as soon you put in the key & haven't even turned the key

Well I am a certified mechanic and I would pull the air cleaner housing open the throttle shoot some carb cleaner in it and if it starts even if only for few seconds your fuel pump is bad. If it doesn't than you need to scan the car with a scanner for no start codes. You can rent a scanner at most automotive part stores for a deposit and when you return it undamaged you get your money back. Usually costs nothing. But if you don't have any pressure on the fuel rail that is most likely your problem. You can clear all the dashboard codes and lights with a scanner if they don't straiten it out on its own. Disconnect battery for a few minutes sometimes that will clear old codes. Only clear codes if you have found out that the fuel pump was bad otherwise you'll need them codes for figuring out the no start problem. Bryan ASE master certified mechanic.

Short in dash

Check the connections on the fusible links. There are youtube videos on the subject

The speedometer sensor - VSS - vehicle speed sensor is a input to the PCM - powertrain control module -engine computer . The signal from the PCM to the instrument cluster for speed info. is sent on a serial data communication network (class 2 ) I would think it would be an instrument cluster problem . Get a used one from a auto salvage yard 15 - 20 bucks an see if it fixes it . If it does ,send your's out an have it repaired .

with the needles off and the scanner set to calibrate the speedometer and all the rest of the needles need to be installed at 1/2 full range with the system on unless otherwise noticed by the scanner.

Most likely your speedometer cable is bad. Good luck.

Sounds strange,look in your manual this may be a warning code if it bounces to the same rpm range. if not check your ecu black box ,if water or damp getting inside it may be causing the problem untill the engine heat dryes it out.

Sounds like an alternator problem. Check belt to make sure it's tight, then have alternator tested.

Only 1000-2000 RPM? Does it do that in any gear?

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Do the following:1)key in the ON position:remove the 7.5 gauge fuse.Tach needle should read "0:". 2)put it back,go on the engine and unplug the green plug on the igniter -the big one,with 5 or 6 wires on it.The needle on tach reading should be zero.If not you have a short circuit on the black wire between that plug and the plug on the conbination meter.3) If the reading is zero with the plug disconnected,the black wire for the tach is short-circuited inside the igniter. I have one available.email [email protected]