Sorry to continue to post, but I need some advice from you guys who know a lot more then I ever will.
I decided to change out my spark plugs and wires on my 99 4x4 5sp v6. I have done very little work on cars,and have never done plugs or wires. I put in Bosch Platinum plugs and Napa wires. Upon finishing, I noticed that it idled a lot better, but I lost some MPG and after a couple weeks it started to bog down. I used to average somewhere from 15-17 combined city and highway. After the plugs and wires I noticed that it was a straight 15 combined on the next tank, then around 12 or 13 on the next one (which was over half highway) and finally on this last half a tank i have gotten somewhere around 9 or 10 i believe. I dont have the means to check my plugs and wires really, being that it has gotten to be around 10 degrees out, theres snow, and i dont have a driveway(I am living up at school about3 hours from home). I want to take it into Tires Plus or something and just have them put in completely new plugs so that I know they are done correctly. Any other ideas? I noticed that one of the wires didnt seem to really catch the plug(just from pulling on it and feeling) but i dont really hear any misfiring....ANY IDEAS OR ADVICE WOULD BE GREAT! If i dont hear anything im going to try to bring it somewhere tomorrow. Thank you and sorry to start a new post.

 

Get rid of those Bosch platinum i heard and have read on different post that they arent good in dakotas, someone correct me if i am wrong

 

You are correct. The platinums seem to be more problematic than they are worth. Switch out the plugs with some pre-gapped Champions. Also, did you put the correct lube into the plug wires to help conductivity? When was the last time you changed your air filter?

 

could be the o2 sensors, ive heard that they go out and dont throw a code...

 

autolite 3923's... no platnum, plain old plugs... it's your best bet in a plug IMO. Start there, then if mileage doesnt improve, yank your o2's and clean them using CRC electronic component cleaner found at the autoparts store... spray into the exhaust stream openings and dont be stingy... let them dry & then re-install.

 

i would say it is the plugs. i switched out my stock champions at 30000 miles and went to the autolite plats, and lost between 45/50 miles to a tank of gas. went back to the stock champions and mileage went back up. at the next plug change i will go with the 3922. but never again with a platinum.

 

Just curious, I have been reading this "don't use platinum plugs in a Dakota" all over the web but have been unable to find a single post that points to a good reason why. can someone enlighten me?

 

i believe that they are longer...they have a tendency of causing the motor to misfire <i thin kive never tested or measured them myself>

 

Travis, thanks for the response, but being a platnim plug only has to do with the material the terminals is made out of, which has no effect on length of the plug. I just fail to see how a blanket statement that they will not work in Dakota's can be made. consider the fact that there are at least 2 distinctly different engine families used in these trucks, with different types of ignition systems.

 

you would think they would be better being that electricity flows easier...but ive been told not so much ill have to do some tests...once it gets warmer than 15 degrees