erronisme

Ive picked up an 03 Dakota with a v6/auto

The previous owner went senile and drove the wrong way on the freeway...yup, he hit someone too...but just barely side swiped the truck.
So to get the old man from driving again the family sold the truck dirt cheap.

I was told that the guy had also put a gallon of windshield wiper fluid in the gas tank.

Before I got it, the family had the fuel pump and fuel filter replaced.

It runs fine, but at Idle it kind of stumbles. The only code is one for the post O2 sensor.

I just replaced the wires, plugs and distributor cap. All of the plugs were over gapped and white. The cap also needed a change too. Also have 2 full tanks and some heat put in there, just to make sure there wasnt any water left in the tank.

Now it runs alot better, but it still has a small stumble at idle.

I want to check the timing, but I am not sure what the timing is suposed be set at.

I am also wondering if the windshield wiper fluid may have messed with the throttle body.

Any thoughts on what else I should look at?

domination

iTrader: (2)

5.9's and 3.9 have a horrible time idle-ing when the throttle body has any gunk in it. I have fixed several that would habitually stall out, just by spraying half a can a cleaner in the throttle, and IAC while its running. You really cant do anything about the timing. If you move the distributer the computer will just compensate it.

lsp408

if there is code for o2 sensor, i would replace the o2

CHEVRACER83

The Post Cat 02 Sensor Shouldnt Cause Any Problems With The Way It Runs.... Unless Its Telling You The Cats Are Plugged..

lsp408

if o2 switching very slow or not switching at all, it will make idle rough. once rev up, it will feel ok. but exhause will smell funny.

since check eng light is on and he said is o2, replace what it needs first and then if it still idle rough, go check other stuff.

no sense to keeping guess what it is until eliminate cause 1 by 1.



just my .02

erronisme

Yeah...O2 sensor will get changed tomorrow... its rather expensive...

But I didnt think that the O2 sensor would cause a rough idle.

Part of the reason I was wondering about the timing is becuase there is a timing mark. I didnt know if there was an initial timing or not.

I guess if the O2 sensor doesnt fix it (at least it will fix the check engine light) then Ill move on to the TB, but the truck only has 25k miles on it.
I watched the O2 sensor voltage on the scanner and it was just stuck on 1.xx volt.

I dont think that the cats are pluged, it runs fine and has pretty good acceleration.

Thanks for the input!!

CHEVRACER83

i understand what you are saying.... but the engine only uses the rear o2's for emissions purposes to tell you if your cats have a problem....

the engine uses the front o2's to adjust the engine parameters.... thts why alot of people delete the rear o2's because they have no bearing on how thw engine runs.

jay_99z

iTrader: (5)

White spark plugs, bad idle.......I would check all vacuum lines. I had the same issues with my 3.9. Found two lines cracked.

erronisme

Welp, I cleaned the TB and IAC valve. It seemed to help alot, but the stumble is still there. It starts easier, but doesnt start right up every time, somtimes it takes a few seconds of turning it over.

3 of the 4 O2 sensor are bad, I rechecked all of them on the scanner. At 60 bucks a pop they will just have to wait.

I checked for vacume lines, but there are only two on there. One for the brake booster and one for the EVAP canister. Swaped out the PCV valve too.

Is there an EGR on there? I didnt look for one when I was under the hood and didnt notice one either.

The scanner or the computer wont allow me to watch the IAC valve to see if its working and the same for the EGR valve.

CHEVRACER83

save the money... replace thr front o2's.... especially if they are reading bad... those could definitely be a problem!!