Hey guys, my 01 Ram 1500 5.2L V8 is having some problems( i think i have a lemon)
When i start it up, it runs fine for say, 10 miles, but then after that, if i come to a stop sign or something, it will die. then i have to give it gas to start back up.

Even if it does idle, if i move it out of park and into drive, it will die.

If i sit in the parking lot and just let it idle, (if it does actually decide to) it will bounce from 400 to 1100 RPM. I took it to the shop yesterday and he said the air filter was clogged and so he replaced it, but now its back and has left me on the side of the road for the second time in a week. If i keep the engine around 1000 rpm, and turn the wheel, the rpms drop about 100, if i turn the air on, it does the same. its like any extra stress, the engine has trouble putting out the power.

The check engine light did eventually come on, but when i did the onboard diagnostics, it didnt give me a code.

Anyone else have this problem before? Thanks, any answers are appreciated.
Jon

 

Clean the throttle body. (DIY in faq section.)

Test the tps. (procedure in service manual, can download it from the faq section.)

After that, if it still does it, unplug the pre-cat O2 sensor, and take it for a drive. If that changes it's behavior (makes it better) replace the sensor.

 

Check the Throttle Positioning Sensor (TPS). It's responsible for sending voltage variations to the PCM. These electrical signals tell the PCM how much throttle is being given to the engine, thus determining how much fuel should be provided. A bad TPS can cause poor idle, pinging, lack of power, inconsistent transmission shift points, rich or lean running, spark plug fouling, poor fuel economy, catalytic converter failure and/or CEL. This could explain the rapid rise and fall in RPM's for your truck and loss in performance. The TPS is an easy fix, and only takes about 25 minutes to do. It's located on the left side of the throttle body. Unplug the electrical adapter, and remove the two torx screws from the unit. Replace the TPS and make sure the new sensor can be slightly rotated with little resistence. Replace the screws and test the movement in the sensor by manually hand operating the throttle. Then start the truck up, and take it for a drive. I just did the TPS, and it worked great! Parts cost approx. $30

 

seems like your talkin about alot of idle problems, not sayin that those guys are wrong but id look at your IAC also on the throttle body on the backside. it will cause it to have a "cam" like idle when its all dirty, it should be shiny, but will get covered in carbon. clean the iac and the passage.

 

It's a fast and free test, unplugging the upstream oxygen sensor, so IMHO it ought to be done first.

Another free and even easier but less reliable test: When the thing doesn't want to idle, park it and run the engine at about 1500RPM for thirty seconds to a minute, then let off the throttle. If that cleans the idle up, the oxygen sensor is probably shot. The sensors have to be above a certain temperature to work properly, and as they near end of life the temperature required to convince them to work properly increases. This test heats the sensor (with exhaust gas), but if the sensor is too far gone already the idle might stay cleaned up for just seconds, or it might not improve at all.

The IAC being dirty will almost always affect idle quality even when the engine is cold.

 

My truck sat with a dead battery for six months. After I put a new battery and fired it up it developed a very rough idle after warmup and threw codes p1391 and p0340. Codes indicated bad crank and cam sensor, intermittent loss of crank signal and/or threwn timing belt.

This is what I replaced that didn't work. Crank AND cam sensor, Idle air Control Valve, plugs, wires, cap, rotor. I even checked cylinder compression just because it was acting like it had a miss.

Guy at Autozone suggested replacing the Throttle Position Sensor (TPS) simply because the truck sat with a dead battery and it reminded him of the fix in other vehicles. I was hesitant to change out the TPS because the truck wasnt throwing out p0123 (which is the TPS code). Put in a new TPS and it fixed the rough idle after warmup instantly. Hope this helps.

 

Thanks for the info.

What brand sensors did you use? Our trucks seem to be sensitive that.