05 5.7 hemi stalls and random misfire

[combatarms]

05 5.7 hemi throws code p0300 all the time and stalls occasionally. i have replaced numerous things and nothing has fixed it yet.
plugs (stock), wires, coil packs x8, trans solenoid pack(had a trans code), egr valve, fuel pump(because it was 2014 advance auto), crank sensor, iat, and throttle body cleaned.

i have gone between different tuning (edge tuner) after code erases and part replacements.

new symptom today is steering, its very hard to turn when sitting, since i see fluid moving in the res. i think the rack is breaking down. i wonder if a failing rack is causing the occasional stalling and when it stalls or bogs down the p0300 comes on. (i haven't been able to reproduce the stalling).

trans... on first start up or after sitting awhile there would be no gear forward or reverse until a few seconds later. the pack was suggested to fix the issue but now seems more like a front pump wearing out. filters were changed and are seated properly.

I'm basically trying to figure out why it stalls and has a random misfire. I'm working to get a second trans rebuilt. Some knowledge that i may not know would be appreciated.

 

[Logan Klein]

I'm not sure for your year, but I'm certain the Hemi has sixteen plugs and sixteen coils. A top bank of 4 and a bottom bank of 4 plugs on each cylinder head. If the truck is stalling/bogging only when coming to a stop this can be an indicator that the engine suddenly is unable to control the idle. MAP (manifold absolute pressure) sensor is a hit-or-miss diagnosis. Sometimes the replacement of that sensor will fix the problem, other times not. There are plenty of reasons for an engine to misfire, maybe the timing chain jumped a tooth and the engine is out of time. This causes bad economy, low engine power output, and can cause the engine to run very poorly if at all. It could also be an air problem (extremely unlikey) or a fuel problem (more plausible). Could be some weak or clogged injectors.

edit: If you find a bad injector, it's best to go ahead and change them all. The same fuel that went into one injector also went through the other ones, so whatever gunk clogs one injector is likely to be found in the rest as well.

 

[LoneWolf3574]

Logan, please don't say things like that unless you know for sure, a simple google search would have told you that any GenIII Hemi has 8 dual fire coil packs and not 16. There is no top or bottom bank, only bank 1 (left/drivers side) and bank 2 (right/passenger side).

combatarms, is your truck throwing any other codes? P0300 is just a general misfire code and typically occurs with another P030* code. A P0302, for example, would be a cylinder #2 misfire. If you are able, try returning to a stock flash on your PCM to see if your issue clears up.

You mentioned a transmission solenoid pack replacement and issues with moving afterwards, is it still doing that or something all together different?

Your truck is drive by wire, meaning there is no cable to the throttle, it is a solenoid controlled by a variable resistor. Take a look at the points on the throttle body and the gas pedal, see if there is build up or wear. Buildup can be cleaned, wear, on the other hand, requires replacement.

 

[combatarms]

Sorry for the long delay in replying but I broke my previous phone and it had this saved.

As my post states it's a 05 vehicle. This particular vehicle is the Daytona edition. For awhile the trouble went away. Today it started up again. First start of the day it had a bad idle. More gas trimmed it to a fine idle just more rpm. I drove about 6 miles and about the 4th mile it got better. I left the store and it was somewhat doing it again. But cleaned up within a 1/2 mile.

As I was driving I floored it and it still has a lot of power so timing is not the issue...

I have flashed the computer with different modes. Towing/race/stock/economy and still same result is given.

Yes only 8 coil packs and 16 plugs all new (plugs are what is listed under the hood)

The only code that was present today was p0300 random engine misfire. Verified through my tuner and with autozones code reader.

When it cools down outside I will check what wires and connectors I can see.

Unless there's a loose connection/wire I really have no idea why this is happening.

Edit (can some people confirm that if you bearly push the accelerator pedal (1/4 inch by hand) the rpm goes to 1500 ish with no control between idle and 1500 rpm)

 

[Marley]

Return your Hemi back to stock tune before diagnosing any issues......you may even find that it's the tuner itself.

 

[combatarms]

Return your Hemi back to stock tune before diagnosing any issues......you may even find that it's the tuner itself.

It's been stock since I did the tune up.