99 Durango Rough Cold Start and Idle
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Joined: Jun 2005
Posts: 14,228
Likes: 19
From: Riverton, UT
I bet the IAC you got was bad, or the port is dirty. Did you actually remove the TB and clean it or just clean it on the truck.
Also hope you used Champion Copper plugs and gaped them at .040 when you replace them.
Just my 2 cents.
Also hope you used Champion Copper plugs and gaped them at .040 when you replace them.
Just my 2 cents.
Registered User
Joined: Oct 2017
Posts: 3
Likes: 0
Rough rider
I have a 99 Durango 5.9 and it runs great sometimes, and like crap others. When it's good, I get about 13.5 mpg. When it's bad I get 10. So far I have replaced my IAC, new cap, rotor, plugs, wires, and cleaned the throttle body. I'm really having a hard time with this. Please help me. When it is rough, it shakes pretty badly, but even though my mpgs suck, performance is still ok.
Registered User
Joined: Oct 2017
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No codes. It changes from day to day. Also, when it's running rough, it also runs a little warmer. I'm changing the pre cat o2 sensor this weekend. Any other ideas?
Registered User
Joined: Oct 2017
Posts: 3
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No, I didn't remove the TB. I am using champions. When I pulled the plugs, they were all clean. I'll clean the TB off the truck this weekend.
Registered User
Joined: Apr 2019
Posts: 2
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I would inspect your ignition coil for damage and output. My 99 Durango 5.9 was doing the same thing and after inspecting the coil I discovered an open gap on the body of the coil housing.
I have a 1999 Dodge Durango 5.9L V8. Only on cold starts, it will hesitate to start and when it does start the idle will bounce between 400 and 1000. Sometimes it will stall out and we can restart it. After about 3 or 4 tries, it will start and run fine. If we drive it somewhere and stop for a bit, then get back in and start it while it's warm, it will start right up and drive just fine. It does seem to be off a little in timing so I am going to fix that, but it also seems to run a little rich from the smell of the exhaust. So far, I have:
1. Checked IAC. It's beautiful and has been replaced recently.
2. Checked Throttle Body. Not dirty and no carbon build up really. I cleaned what was there, but nothing much or severe.
3. Checked battery. sitting at 12.5 while off and 13.7 when on and running. So not the battery or alternator.
4. This truck from what I have read up on, does not have an EGR valve. So that can't be it.
5. One thing I did notice though was the throttle body cover, when I took it off, the gasket between the throttle body and the cover was broke apart and when I picked it up, it just broke apart more.
6. Spark plugs and wires are all new
Also I have been reading a little bit more and have a few possibilities. Let me know what you think...
1. O2 Sensor
2. Fuel Injection Cold Start Valve Plug
3. PCV Valve
4. Distributor Cap and Rotor
5. M.A.P. Sensor
6. Throttle Position Sensor
7. Air Charge Temp Sensor
8. Coolant Temp Sensor
*There is no MAF sensor in this truck and from what I have read no EGR valve either.
Please any help would be greatly appreciated.
1. Checked IAC. It's beautiful and has been replaced recently.
2. Checked Throttle Body. Not dirty and no carbon build up really. I cleaned what was there, but nothing much or severe.
3. Checked battery. sitting at 12.5 while off and 13.7 when on and running. So not the battery or alternator.
4. This truck from what I have read up on, does not have an EGR valve. So that can't be it.
5. One thing I did notice though was the throttle body cover, when I took it off, the gasket between the throttle body and the cover was broke apart and when I picked it up, it just broke apart more.
6. Spark plugs and wires are all new
Also I have been reading a little bit more and have a few possibilities. Let me know what you think...
1. O2 Sensor
2. Fuel Injection Cold Start Valve Plug
3. PCV Valve
4. Distributor Cap and Rotor
5. M.A.P. Sensor
6. Throttle Position Sensor
7. Air Charge Temp Sensor
8. Coolant Temp Sensor
*There is no MAF sensor in this truck and from what I have read no EGR valve either.
Please any help would be greatly appreciated.
