AlpineRAM

Had a 99 yesterday with problems quite similar to what you have.
Searched by measuring the supply voltage to the CPK, found it rather low (3.5V)- started unplugging other sensors while watching the voltage.
Long story short - the MAP sensor had shorted internally and had pulled down the voltage just enough to mess with crank and cam signals but not enough to trigger a fault code for the MAP.

turbox2

Well here it is may 6th and still not solved problem all wiring ok 5v like it should starts runs real ruff with tac engine light comes on loose tac idles fine code says cam sensor bad replaced still says bad cam sensor tired

AlpineRAM

Did you measure the 5V while running?
Is that 5V supply stable during all the phases- start, rough running and normal?

Did you try to let the engine run with only power to the VP44?

turbox2

I will try this after it stops raining and post it

AlpineRAM

I think that you will find something almost trivial, but also quite "far away" from what you do expect now.
That's why I recommend to start isolating the problems.

Try to make the engine run in "dumb mode", just +12V and ground to the VP44, should idle OK, if not the problem is in the VP44, if it does you know that the IP is sane enough to throw a code if it has any other problems.

Do you have any other problems with this truck- anything else that does not work? AC, charging etc?

This could help with chasing that gremlin.

turbox2

Replaced ecm with another new one was nc to me still same although oil pressure gauge has stopped. Working loose connection I'm guessing ,tired of working on it for today maybe Mother's Day will be a better day

AlpineRAM

What I think is that you might also have a bad instrument cluster- or wiring towards the cluster.
If you short the bus somewhere you will get erratic indications on the cluster (because it is only told ba the bus what to show) and on the other hand you get erratic commands to the ECM, the PCM and the VP44..

turbox2

Well have 5 volts while running will idle with 12 volts to pump with everything hooked back up now and then the tach tries to work engine changes rpm for a sec then back too same problem. It sure runs bad before tach cel comes on and tach quits. I guess since the scanner tells me it is a cam sensor and I have put a new one in it it might be bad. That thing is a real bear to change mite pull the 44 this time I got hands the size of Texas.. Just about ready to say I'm whipped but not yet

turbox2

Ok took pump off this time replaced cam sensor for the 2 nd time. Checked all wiring did notice the magnetic pull was not very strong but it worked. Put everything back together still says I need a cam sensor . Pulled the connector to the Ecm and cleaned it still no change. I still have the oil pressure gauge not working that started with the 2nd ecm. I did put the old crank sensor back in also. Still open for any ideas men I miss my truck I'm 60 yrs old and have never been stumped like this

KATOOM

turbox2, I just sent you a private message.