Ok, this is a new start to a old thread from last fall. Gave up for the winter and now that the snow is gone... time to start again! Problem, briefly, is a Dodge Ram 1500 with a V-6 (4x2), 136,000 miles and it runs VERY rough. Kinda like it is missing? When I got it... it started with NO problem. Idled so, so and blew NO smoke at all. Drove it home (5 miles) and as long as it was in drive/Low2 it ran fine. As soon as I shifted it into Drive... rough and into O/D VERY rough. Higher the RPMS, the better it ran.

Done: Compression check...OK! New Plugs, Cap, Rotor and Coil. Replaced within the past year by the former owner... Cat, O2, EGR, Fuelpump (in tank).

Now keep in mind this is NOT a performance truck. Just a get wood, groceries, and my butt to work - truck. Any and ALL comments are greatly appreciated.

 

check all vacuum lines. may have a leak. verify IAC is working. is it giving you a check engine light?

 

Exactly how rough is it?

Apologies to anyone who has one, but the 3.9 is a slug.

I haven't seen one yetthat wasn't low on power and they all shake at idle!

Did ya check the plenum? they blow on these too...

 

What is a IAC and what is a plenum? No it is not throwing a code (that would be to easy...lol). Talked to the former owner a little today about the truck and he said that the "rough" running was a gradual thing (if that helps). As far as how rough? Just like, well it is hard to explain... but it is just not up to par. It will go up and down the road. Just like, one plug wire is off... a little flooded... timing off. But it starts right up... with no hesitation, and idles instantly (no feathering of the pedal at all).

 

Good luck. I am hopefully near the end of my search for the answer of the same question regarding my truck. I have replaced quite a few parts and thankfully the truck is now running better but still not perfect. The major repairs included replacing the exhaust system (everything but the exhaust pipe), replacing the timing chain and sprocket and the distributor/oil pump drive shaft and bushing. If you haven't found this out yet, the engine timing is controlled by a sensor mounted at the rear of the engine block and you can't change the timing. Turning the distributor does not change the ignition timing. Instead it changes the fuel injector timing. If this has been done, gas is not coming into the engine at the correct time and this can cause the rough running. I have also changed the obvious - plugs, wires, rotor, dist. cap - and the not so obvious - o2 sensor, throttle position sensor, map sensor, fuel injector o-rings. I replaced one leaky vaccum hose. The only diagnostic code displayed was for a bad coolant temperature sensor. I carried it to a Chrysler dealer's shop and they changed one fuel injector which as far as I could tell made no difference. Recently, someone posted a suggestion to my thread that I change the fuel injector connector clips with an aftermarket part by MSD. At first, I couldn't sense any improvement. But as I have continued to drive the truck it has become obvious that an improvement has been made. I still have a slight hesitation under load and an occasional backfire through the intake, but the magnitude of the problem is less than 10% as severe as it was to begin with. When I replaced the distributor drive shaftI set my fuel timing mechanically. I plan to have it checked with the DBII instrumentation. Possibly that will complete the quest. Basically I had compound problems. Fixing one problem alone did not cure everything but each thing I did helped and made it easier to pinpoint the next repair needed. The only thing that I did that I cannot say for sure helped was replacing the o2 sensor and the map sensor and the fuel injector that the Chrysler shop replaced. Good luck on your quest.

 

Oh, Granpa49... I am not going to put that much money into this truck. If anything, It is going to be sold for 400 bucks! That is a deal and truck would make a good wood hauler. Just thought I could maybe figure this thing out and start driving!

 

Stonehouse -->

Idle Air Control (IAC) Motor - (IAC) Used to control idle speed on fuel injection vehicles. A valve that allows air to bypass the throttle plate(s) increasing idle speed. The valve is operated by an electric solenoid or motor. The vehicle computer controls the amount of opening to regulate idle speed for varying conditions such as cold start and air conditioner compressor load.

Found a good website ,, maybe we should PIN it?

http://www.rockdaleautomotive.com/glossary/