Hi all! Been awhile since I've posted. I've got a '95 Ram 1500 5.2, 4x4. It's always ran as smooth as any car I have. But all of a sudden, it started running rough and doesn't have full power. It literally happened overnight. I filled it up with gas, towed a trailer about 150 miles, ran great. Next morning, it idled funny, and when I went to drive away, it shuddered and shook. Feels like a misfire. But there are no codes being flashed.

So I checked the plugs (good), put new plug wires on, replaced the cap and rotor, cleaned the throttle body, checked the fuel pump pressure (good), checked the injector (had power), checked the o2 sensor, checked the TPS and the IAC sensor, and called the gas station to see if they got some bad gas (good). I put an emissions machine on the tailpipe and the hydrocarbons are off the scale. So I figured the problem must still be electrical. I then replaced the front coil, and that made it run better, but still not perfect. I'm really scratching my head on this one! Any guesses on what else this problem could be?
Thanks guys.

 

Running rich... so, maybe a temp sensor, maybe a failing crank sensor. Have an O'scope you can put on it, and see what coil output looks like?

 

How old are the o2 sensors?

 

You checking the O2 sensor but I would replace it. Cheap and easy.

 

They are two years old. Look good.

 

Replacing the coil is what made it run better, but it's still not running perfect yet.

 

That is certainly cheap and easy. But wouldn't a bad O2 sensor throw a code?

 

I had one that was bad and didn't throw a code for a long time (that's a whole long story in itself). What brand sensor is in it?

 

You can test the O2 sensors by simply unplugging them. If the engine runs better, sensors are bad, if it still runs the same, your problem is elsewhere.

 

Not necessarily. I had put in a bwd sensor and it worked a couple years then acted funny. Never got a code. Replaced it with ntk oem. These trucks have very broad parameters and rarely throw codes for anything. Only one I ever had was for speed sensor. I'm at 238k.