420A Weird RPM

[livedsm4g63]

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This is my 95 420a with the engine off, key to the "on" position, rolling...

I replaced the cam sensor, coil, and plugs. Im throwing in a new fuel filter tomorrow. My 420a knowledge is lacking.

When the car is on, at idle the car runs fine. As soon as I start to move the cars RPM jumps all over..
Btw, the MPH has never worked since I got the car. Everything was working good then all of a sudden it started to miss while cruising. Now its so bad the car can barley be driven.

Thanks for your help!

 

[DJ Raydiate]

How fast do you think you were rolling with the key on? That may be the reason that the RPS are jumping like that. Do they do that during normal driving?

A friend of mine had an erratic full pump/miss issue with his 96 RS and it turned out to be the fuel pump screen, It was so caked that it wasn't even funny. Just a suggestion.

 

[livedsm4g63]

I was going 45ish mph and it slowed down to around 30 mph. I find it hard to believe it is fuel related. A sensor is acting erratic while the car is in motion. Causing the RPMs to jump.

It does this while the vehicle is on driving as well, but it does not do it while stationary.

As I stated, the Cam sensor, ignition, and plugs were changed.

 

[livedsm4g63]

Codes were 12, 25, 11, and 55

25 an IAC so I ordered a new one.
11 is either timing, cam sensor, or crank sensor. Since cam sensor was change I have a crank sensor on order. Highly doubtful its the timing due to the fact that it is random, when the car breaks up and goes haywire.

 

[BlackKnight2013]

Code 11 is intermittent loss of crankshaft and/or camshaft position sensor signals to pcm (powertrain control module); complete loss of crankshaft position sensor signal to pcm; or timing belt skipped one or more teeth (from Haynes service manual).
the rpm is read off of the crank sensor, the crank sensor is a hall affect sensor. the signal for the rpm gauge goes to the engine control module (ecu) and then from the ecu to the cluster.
at the crank sensor (should be on the right side of the engine, which is the firewall side, just above the oil pan to the left of the oil filter) you should have 5 volt reference (some of the chrysler powertrain sensors have 8 volt reference systems) from the ecu, a ground wire and a signal return wire. test the wiring harness side connector for the crank sensor, with the key on and engine off, with the negative volt meter lead on battery ground and positive lead on a back probbed t-pin (small metal pin pushed into the back of the connector next to the wire) on the yellow wire, you should see 8 volts. on the L-W wire you should see 5 volts with the connector unplugged and back probbed. with the negative lead on the black with green chaser wire and the positive lead on the positive battery post you should see 12 volts aprox to indicate a good ground. if all this is correct at the connector try a known good crank sensor. also be a good idea to verify the timing of the timing belt.