Hello all....this is my first time posting on a site like this so I hope that I am doing this the correct way. Also before I get started I would certainly like to thank everyone who has played a part in creating this site...it has been a real help for me
I have a 1997 dodge dakota 3.9 4 wheel drive automatic. I have a problem with the vehicle sputtering and running ruff. It will start and idle fine..then as I drive within a block or so it will start to sputter a little bit..then it will progress to a feeling like it is running only on 2 cylinders. When I first noticed the problem about a month ago it would come and go...but now it seems to happen all the time
Codes were at one point : Random cylinder misfire, and 02 upstream high voltage

"Things I Have Replaced"
Crankshaft censer
Camshaft censer
Wires
Plugs
Cap
Roter
Coil
Pcm
o2 censor from the dealer "upstream"
PCV Valve
Crankcase breather

"Thing I Have Checked"
Fuel pressure "Put guage in windshield..drove with and without problem occuring...steady reading always good"
Map censer 4.7 at output....less 1volt per 5 psi
Tps censor "closed and wide open" checked good
Fuel injectors...Basic test all within range of eachother
After all this there are no codes...but still runs like crud after a block or so...also does it in nutral...and will do it even if I restart truck

I also followed the instructions for the coil wire and extra grounds to fuel rail and coil. Also checked coil pigtail.......... I am so lost at this point !! I don't know what else to do. Any feedback would be greatly appreciated. Thanks in advance for any help

 

Have you checked the injectors? Check the resistance across each one.
Also have you checked the EGR and all the lines?

 

yes checked ...basic test shows good...all injectors close readings

 

where is the egr?

 

Coolant Temp Sensor? Checked?
Fuel Pressure?

 

I don't know where the EGR is on a 3.9. I have an 03 4.7.
Oops, I just looked it up and there is no EGR on that engine. At least you know it can't be bad..lol

How about vacuum? Have you checked for a vac leak somewhere?

Sorry, I didn't see that you had checked the injectors and fuel pressure in your first post.

 

I did a basic spray vacume hose with carb cleaner test ......And I have not tested coolant temp switch yet...would that cause extreme miss like I have ? And if so...how do I test it ?

 

I also forgot to mention that I disconnected the exhaust after the upstream o2 censer to see if a clogged cat could be my problem......but there was no change...still had problem "except realy loud when driving"

 

Does it only do it when it's warmed up a bit? Did you see the O2 code AFTER you changed it?

A bad oxygen sensor can cause all these problems.

Do you have a scanner? Can you get some live data?

 

Yes a bad O2 sensor can cause these problems.

A faulty CTS (Coolant temp sensor) can go bad either open or closed. On startup, depending on which way it fails, it could send a "cold" signal which is what the engine needs for a cold startup, but once the engine warms up it still tells the PCM that the engine is cold causing it to run waay too rich.

Have you checked the condition of the plugs? Is it fouling the plugs? If so it fuel fouled?