I bought a 97 Dakota Sport.. 3.9 Manual from a friend.. The truck has been sitting for several years.. So I knew it needed a few upgrades.. Installed New Brakes, Brake Lines ( all of them) Power steering line.. Head gaskets.. New exhaust system.. I went with Mangaflo 2 " Duals .. Split at the muffler..

The problem I am having now is I ran about 4 gas tanks through it and now it was sputtering when I was stopped at a Sign... Surged a bit going down the road So I thought it was a fuel problem... Well $250 later and a couple hours in the shop I got the new Fuel pump installed and Fired the truck up.... Backed it out ran it up and down the road... Let it sit and Idle to watm it up while I cleaned up my mess.. and Went to leave it Quit. as soon as I hit the gas.. Funny thing is... the Temp gauge went from 190 to 0 minutes before.. ( have noticed it doing this a lot lately) So I bought a new temp sensor and Thermostat.. Going to instal them... Installed new plugs and Wires.... Took it to a Shop today to check the codes.. (Check Engine light) was 3 of them Fuel Pressure, Air and Temp... What am I doing wrong?? ANy Ideas?? Spark pick up coil?? ECM?? Thanks In advance

 

We need to know exactly what those codes were. You've changed a lot of variables and any of them could have caused a problem. Or maybe none of them did. It could be something altogether new.

 

I think the temp fluctuation is due to your mechanical fan is going bad.


The other stuff may benefit from a good hard run and get the engine hot also run a tank or two of quality fuel system cleaner.


You may want to run with a thin detergent oil for a month or two to be sure the oil passages are not gooped up and change it in a month. I would take it easy on it for some time till everything clears out.