I hava a 1998 gmc with a 5.7 began skipping have

Have you confirmed that its not a security issue? Did it die suddenly or was it bogging out for a while? Have you scanned the engine?

The cam and crank sensors have the same power wire. Go after that one. They also have the same ground, but other sensors connect to it also. So it's not the ground. And they have separate return signal wires. Not them either.

There is a cam sensor located under the distributor cap. Is that what you are trying to replace? If so remove the cap. Remove the rotor. Rotate the crankshaft with a socket and ratchet via the crank pulley until the square notch in the exciter ring lines up with the cam sensor. Remove the two cam sensor screws and remove the sensor.

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If a random multiple misfire code appears , and electrical system checks out Ok, need to do a fuel pressure test at the fuel rail (Drivers side) if checks out ok, it very well can be sticky fuel injectors.If injectors leak by can cause to much fuel dispursed into engine, sometimes a bottle of lucas fuel injector cleaner will do the trick, opens up the poppets (injectors) although the (Spider Injector) has an electrical pulse that is supplied from the ECM (computer.) The spider injectors definitely go bad some sooner than others! Not a pleasant job also an expensive job if u are not doing it yourself! If your vehicle was fine before this started happening go back over everthing u have done, check each wire out with a noid to see if spark is correct ( A noid plugs into end of the wire that goes onto the sparkplug, check each wire one at a time, u can purchase a noid for this vehicle at your local autoparts store) Not saying this is definitely the problem, there are many things that cause these problems,crank sensor, cam sensor, tps mass air flow map sensor intake leaks and vacuum leaks etc etc,u can check for leaks by spraying down intake and vacuum lines with a can of carb cleaner, look for a change in the idle when u are spraying it down How do we know? been thru it all to often! GOOD LUCK! 1998 GMC Jimmy 4.3 Liter Vortec V- 6.

check your crank position sensor and the wiring that goes to it. you will notice that the bundle of wires passes by the frame if you follow it and look for worn off insulation at the frame, the wires may be shorting to ground because of this. if this checks good i would guess its the cap, change it out anyway if you have not done so already recently, its good maintenance and cheap.

starting definately has a lot to do with the crank/cam position sensors, but it wouldnt have nothing to do with hot or cold weather, oxygen sensor will make the vehicle run too rich if its out, you will smell fuel very strong out the exhaust, that could make it run sluggish also, and usually if the mass air flow sensor goes out the vehicle wont start at all...

If you are sure they said, a distributer cap a roter and a distributer, there is a problem! Because on a 1998
plymouth, there is no distributer or cap or roter.
Your cam sensor along with the crank sensor-temp sensor and a few other sensors, send a signal to the
powertrain control module, that sends a signal to the
coil pack(that you said was replaced) that fires the
spark plug. I would hold off from having any further
work done there, until you can check out what they
say they have already done. Ask if you can have the
old parts they replaced so far. You will want to have
an OBDII scan test done, to see what codes come up. It should have one of the first tests they did.
If I have read your post correctly, have them write an
estimate for what they will replace next. This info. is
based on the car being a 1998 plymouth and not a
1988 I would not wan't to acuse somone of anything
based on a typo. Hope this helps. Good luck.

i have a 06 sierra that done the same thing and it was the distributer gear stripped

check the ecm fuse and power wire from starter

check the wiring harness at the coil,sometimes that plug will get loose or dirty resulting in a no spark.
The only ign system parts are the crank sensor,cam sensor,dist,dist cap,rotor,spark plugs,wires,and coil,and the ecm which controls all of these,is there a check engine light on?
run a scan tool to check for stored codes or system events stored in the ecm.