I got a misfire code. I changed the plugs wires distributer cap and rotor. When doing so I messed up the plug wire orientation. Started it up and it ran like **** so I quick turned it off, then fixed the wiring. Since then the truck does not idle, it just stalls off. It will start all day long but after it revs up at start and settles out it settles all the way off.

I then checked my fuel pressure (40) and checked compressions (140). I then cleaned the throttle body and changed the TPS and the IAC. The truck refuses to stay on unless I keep my foot on the pedal.

I went to the parts store assuming I was going to be buying a fuel filter, come to find out that there is no fuel filter, per say. The guy there suggested the sending unit may be bad? I thought this only displays the fuel gauge. So I'm thinking it must be either injectors or the fuel pump? Would either of those effect the idle?

 

Need some more info year and motor and any other codes that are coming up

 

Don't go after fuel first necessarily. Idle air flow would be the first thing I would look at.


See if there are any stored or active codes.

 

Did you reset your computer after your tuneup? A battery terminal disconnect while doing the repairs would reset it.

SJ03

 

My bad. It's an 03 1500 5.9L

I initially threw code 305 for a misfire, so I changed out the plugs wires and cap. I cleared that code and haven't gotten a code since. I wish I had a code so I knew what to check!

 

I took off the positive battery cable and held it to the negative to "clear" the computer but that didn't seem to work. I'm not sure if I did it properly or long enough though either.

I've noticed people saying to disconnect the battery while doing these things on a few other posts as well… I did NOT have the battery disconnected when I did the work. Bad?

 

I doubt touching the 2 cables has any benefit. A good 20-30 min disconnect would suffice. Would take a few cycled cold starts to know if it's fixed or will kick up codes. Keep us posted.

SJ03

 

so Lets recap:

you got compression at 140psi on all of the 8 cylinders....
You got 40psi fuel pressure at both rails [assuming both rails]...
When you start the truck it revs up and idles but then [slowly?] decreases revs until it stalls itself out...?

You've changed the TPS and IAC and had no change...
you've changed the plug wires and the distributor cap & rotor...

Have you tried changing the spark plugs? If so, did you put in copper core plugs? Some of our trucks don't seem to respond too well to anything other than copper core plugs....

Seems like this was all caused by mixing up the plug wires, which would definitely cause the computer to throw a bunch of codes due to incorrect timing on the cylinders you mixed wires up with... So I'm almost inclined to think that the truck's computer (PCM) may have put it into Limp mode, which would stall the truck out at idle if you have spark plugs that are in bad shape....

Mixing up plug wires can also cause damage to the spark plugs depending on which you mixed up and what the firing order is, so I'd pull them again and check the gap on each of them and then re-gap and re-install as needed...

Next thing that could happen is a Crank Angle Sensor failure due to the mixed up firing order...

Oxygen sensors wouldn't throw a code upon start up b/c the truck doesn't read from them until they warm up, so it will run on the MAP and IAT sensor until then. You might want to run a check on the MAP sensor and the IAT sensor as those are what would tell the PCM what the temperature of the air coming in is, as well as what the Abs. Pressure is inside the manifold.

Next thing I'd check would be the valve springs, which you'll only need to pull the valve covers to check. You might have a broken valve spring... (this is unlikely, but we're running out of things to check)

Some other things to check along the way are:

Grounds to Chassis (might have a bad one, or knocked one)
Put a new Ground Wire from the throttle body bolts to the chassis
Battery Test (might have a bad cell)


we can go from there...

 

That only works if you dance on your right foot under a full moon, holding your left earlobe in your right hand while chanting "Toga! Toga! Toga!"

Meanwhile, this sounds like a broken valve spring. Oops, now that it's not a Hemi, the valve spring issue probably isn't in play.

 

Ok I pulled the injectors and tested resistance and tested them with a battery and cleaned them out. They all function fine. I pulled the battery terminals and left that sit for like 8 hrs (might be over kill but I fell asleep). Put it all back together and have the same thing. Sometimes it feels like it still misfires.

I did replace the plugs initially and used champion copper core plugs.

Would it be wise to buy stock mopar cap, plugs, and plug wires? Or continue looking for a bad sensor? I guess Id do the MAP sensor next.

I had the fuel pressure gauge on the whole time it ran and never lost pressure when it shut down.

Another thing is that it tries to stay on... When I start it, it revs to 1800 then settles out to normal for a bit, then the idle bounces around a bit and then drops to 500 for a spell and then dies.