1999 dodge Durango 5.2l V8 4x4
 

I have a 5.2l dodge Durango 99, it has 120k miles and already starting problems. When she's idling, she'll idle extremely low but wont die, don't know what would be causing that. Then I have another problem I've invested almost 600 into her. Everytime I get her around 45 mph she stars jerking and losing power while backfiring and shooting out sting fumes. But after 5ish miles she'll run correctly until I shut her off and her computer restarts. I've cleaned the spark plugs, heads, pre-cat 02, 02 sensors, spark plugs/ wires, throttle body, and map sensors. I'm fairly new to car (only been working on them for about 2ish years). Please help.

Have you considered a complete ignition tune? I have had similar issues with my wife's 99 Durango and when I took the distributor cap off, I found evidence of moisture. Replaced the cap and rotor while checking wires and all was well.

And clean the throttle body. Take it off the engine to clean it.... Pay special attention to the IAC well.

I guess you meant removing of idle speed motor, not throttle body?

Thank you for the quick reply. I'll look into that first thing tomorrow morning. If it is the problem I would owe you my life. I've been struggling on this problem for almost 3 years and had no progress.

Both. Much easier to work with/clean when it's off the engine.

I took off the distributor cap and found no moisture, IAC was still intact. How can you tell if the IAC is bad? Haven't had much luck with the throttle body yet.

Truck
 

I recently removed the throttle body and cleaned everything on it, took special care around the components. It fixed the randomly dying when I slow down but still chugs.

I'll give a better description on the problem,
As im driving maybe around 20-50mph it starts to somewhat jerks/hesitate. As if its dying from no gas. You can pump it and it'll accelerate but go down quickly while jerking
But if you remain the same amount of pressure on the gas it'll eventually go through the course and backfire.
I was thinking the gas line could be leaking causing it to get too much air and not enough gas. The rotor on the distributor could be lose. A crankshaft could be jamming.

When it starts to chug/hesitate/backfire
It feels like not all the fumes are exiting the exhaust, then when it backfire it seems to clean itself up. I also get this horrible smell when it's chugging.
Please help.

Sincerely,
Chevy

Getting any codes? And pending codes? (Need a scanner to get those, parts store scan tool should be adequate.) Sounds like a misfire issue. have you done the tune up yet?

Codes
 

These are the recent codes I've received in the past few weeks,
PO443
EVAP Purge solenoid circuit

PO141
02 Sensor 1/2 heater performance

Dodge (ABS 65)
Open Power Relay Contacts

Dodge (ABS 45)
Open Iso Solenoid Or Shorted ECU output LF

P1594
Battery Voltage High

Don't know if any of those codes could cause a misfire, but I'm not that experienced on vehicles yet.

Battery voltage high?? May wanna look into that one. Could cause some interesting problems. I don't *think* the O2 code would cause it though, that's the rear O2, and it basically is just to monitor the catalytic converter. ABS codes certainly won't.

I'll look into it tonight.. thank you for helping me.

Alternator
 

Get the alternator tested.

Fuse
 

Check the 140 amp fuse, might be loose

Alright, update.
These are the parts I just recently changed.
Bought a brand-new distributor cap and rotor, brand new catalytic converter, new spark plugs again and a IAC.
Cleaning the TB and replacing the Iac has fixed it randomly dying while shifting or coasting.
My Father said it sounded like a piston or valve sticking but it wouldn't just clean itself up.
I have yet to check for any vaccum leaks or shortenings. I fixed the battery code I was getting and still nothing new.
It quit backfiring when it chugs and now will chug until from 45-50 until I get down to 10-15 and randomly start accelerating again and will start over after 2-3 miles. Sometimes I'll get lucky and only experience a single chug there and then another on the way home.
I would extremely appreciate if you have any information that I'm missing, anything that could help me track down this irritating problem I've been experiencing for years.