I have been reading many threads and am at a point where I need help.
I have a 1999 1500 with a 5.2L engine. It was sputtering at low throttle and then wouldn't start. It was intermittent for a while, and not won't start at all. I assumed it was a fuel problem, so replaced the fuel pump. That didn't work, so I replaced the camshaft position sensor and the crankshaft position sensor, still not working. I am getting fuel and spark. Would the IAC cause the problem? Is there a way to test the PCM? Thanks for your help,
Ken

 

Will it start if you step on the gas a bit? (or even floor it?)

 

Nope, won't start no matter what.

 

The IAC shouldn't cause failure to start.

You say the fuel is present but not if it's at correct pressure, and that you have spark but not whether it's coming at the correct time and is at all cylinders. That makes it hard to know where to start. Check into those things.

Then define "sputtering at low throttle". Was it missing? Backfiring? Afterburning? Pinging?

First bit of advice: Don't just throw parts at the thing. Start by identifying a quantifiable symptom, continue by examining/testing components that could plausibly cause the quantifiable symptom and eliminate possibilities in the largest chunks possible. For example: If you've got good fuel pressure and it remains good when you're cranking the engine over, you've just eliminated the fuel system from the injector rail through the tank and all the way back through the electronics to the battery. When you find a faulty subsystem, do your best to find the exact middle of it and test for proper operation there -- if it's good in the middle you've eliminated everything behind it, so find the middle of what remains, and so on. The more time you spend thinking, the less time you spend refilling the bank account.

 

tune up ?

 

clogged cat...unscrew the pre-cat 02 sensor, and see if it will run better

 

Thanks, I will get some more information. While driving at slow speeds the engine would sputter and try to quit, no problem at increased or full throttle. So, I replaced the spark plugs, wires, distributor cap and rotor. It drove well for a while, then died on me. This is why I thought the fuel pump went out. I was not aware at the time about the fuel sync, and other possible problems. I put a spark plug against the engine and saw spark while cranking. I will have to get a pressure gauge to check the fuel pressure and make sure I have good fuel pressure. On the scan tool I got a problem code for the camshaft position sensor and the O2 sensor. That is why I replaced the CPS. I will remove the pre-cat O2 sensor and see if that works?

 

theres one right before the catalytic convertor, try unscrewing it with a wrench, and see if it will run better.

 

Took out the pre-cat 02 sensor and she will not start. I will get a fuel pressure gauge and test the pressure while trying to start. Will also verify that the spark is happening at all cylinders. I really appreciate everyone's help.
Ken

 

Try...take the distribitor cab off and wiggle the actual distibitor shaft. if theres play than replace the shaft and you will be good to go. This identicle problem happened to my dads jeep. Also might want to look onto gettin a coil.