Hesitation, skipping, bogging down

[unicorncomputer]

I've been battling an issue for over a year now. It started by getting a P0300 engine code, random mutli cylinder misfire.

2004 2500 5.7L Hemi 96,000 miles.

The truck would bog down like its not getting air or fuel.

If you put the pedal down to the floor, it would ramp up roar and go.

I ended up finding that if I disconnected the battery, let all juice drain so all computer codes and readings would clear, it would run fine for a while, could be 10 miles could be 500 miles, was weird.

I changed the spark plugs, put in the champion copper like I read here. I changed the spark plug wires.

I have changed the IAT and MAP sensors.

I had an o2 sensor bank 1 sensor 1 go bad, took a long time , but got that changed, now I still get code for Bank 1 o2 heater circuit error.

I am not sure what to check for next. I do have a code reader and it does show some live data. I have noticed the bank 1 Long Term fuel trim going severely negative when its running like crap.

It is getting worse so I need to figure something out.

I am thinking about testing the fuel injectors, but don't know what the Ohm reading should be on them. I can't seem to find it on google.

I was wondering about the fuel filter or pump....

Any suggestions or ideas on where to check next?

I'm no mechanic and diagnosis is my downfall. I can fix most things once I know what is wrong, thank you google, youtube and forums.

If there is anything I can provide you with to help please let me know and I will do my best to get you what you ask for. You might have to spell it out some. My schooling is in computers, but I have done a fair bit with vehicles..

Thank you for any help in advance.

Steve

 

[Krein]

I know depending how long your o2 sensor was bad/ throwing a code can cause your truck to run lean/rich which in turns can kill your catalytic converter. ( I know from experience) That being said i would seriously think about replacing the cat. Had the same problem on a previous vehicle. Hope this helps

 

[Karlsweg]

Agreed on looking at the cats.

 

[Hootbro]

Could also be a intake manifold leak.

 

[unicorncomputer]

I know depending how long your o2 sensor was bad/ throwing a code can cause your truck to run lean/rich which in turns can kill your catalytic converter. ( I know from experience) That being said i would seriously think about replacing the cat. Had the same problem on a previous vehicle. Hope this helps

The problem had started prior to the o2 sensor code though.

 

[unicorncomputer]

Could also be a intake manifold leak.

How would I look for or test for this?

Thank you,

Steve

 

[Karlsweg]

Sparingly spray starting fluid around where the intake bolts to the heads while engine idles. If rpms increase, the intake is sucking in air past the gasket.

 

[Hootbro]

Sparingly spray starting fluid around where the intake bolts to the heads while engine idles. If rpms increase, the intake is sucking in air past the gasket.

^^^^^^^^^^^^^ What he says. Just be careful with starting fluid as it is flammable so use it sparingly. Could also use a spay bottle of water sparingly and instead of a idle increase, the engine will bog down more. You also want to try it on the other vacuum line connections in addition the intake manifold.

Plenty of Youtube videos out there showing this method if you search.