01 1500 RAM RPMs frequently jumping 4K - 6K momentarily

Unplug 02 sensor and rap it up so bang around then take it for drive

check for vacumme leaks sonds like a hose came off if nothing found replace teh idle air controll motor

Have you had the TPS calibrated? it needs to be set at a position with a specific resistance to set the correct idle speed, There is also no point try to do anything while you have the vacuum leaks as this make tuning impossible.

Hello there,

This is a normal operation, all your doing is hitting the rev limiter. It's there to protect the engine from over revving. The Powertrain Control Module or PCM cuts fuel to the engine intermittently to keep the engine from revving past a predetermined RPM when in "neutral", and in "park" if it's an automatic. Just in case something like a foreign object or a small child or animal were to inadvertently depress the accelerator pedal and rev the engine too high and damage the engine in result. I hope this info helps, and just for peace of mind, I am a Master Certified Ford Technician. Enjoy your new exhaust!! I'm sure it sounds great!!

I don't know if it would cause the shaking and vibrations, but for the smoke it could be loose nuts or broken studs on the exhaust manifold -- when engine is cold check each of the nuts (there should be 8) to see if they are loose or missing/broken; you may have to remove a heat-shield in order to gain access

I had the exact same problem on my 04 GC. I put some Techron Concentrate Plus Fuel System Cleaner in from Wal-Mart and it seemed to fix the problems right away. Let me know.

There is a vacuum leak somewhere in the intake system. A very common problem on these cars is a PCV valve that gets stuck open and replacing that first is very cheap. If that doesn't solve the problem, then you'll have to go hunting. Listening very carefully for a hissing sound in the engine compartment will often lead you to a hose that is off or a gasket that has failed. You can also spray small amounts of aerosol carb cleaner at suspect areas to confirm the leak. The engine will change revs when fed the carb cleaner.

I know exactly what you are talking about, it will go high to about 2 to 4k rpms, then back down to 1k in intervals of about 3 seconds. It is either the idle air position sensor, or the throttle body position sensor, hondas are famous for it. The parts are cheap, about $20-$30, and fairly easy to install when you find it. I suggest a Haynes Manual for installation to make it a lot easier if you don't know where it is. Good luck, hope all goes well.

those sensors could cause the issue, clean the MAF 1st, also clean the idle system using the following procedure, the IAC can cause cruise surge. I use this to cure these problems all the time.

Here is the most common cause of surges and stalls and low idle, it is the idle speed control air-bypass valve (IAC) and throttle valve, they get full of gunk over the miles and cause idle issues (stalls, low idle) like yours, Get a can of intake cleaner from any local parts store, not carb spray, intake cleaner, it is made by a company called CRC, remove the air intake hose to the engine, hold the idle high so the engine won't stall, then spray the can of cleaner into the intake while keeping the engine running, use at least 1/2 the can, shut down the engine and disconnect the battery for 5 minutes, then restart and complete a number of mixed driving cycles, town, freeway, stop and go etc., after a few days the problem will go away as the system will relearn to the clean intake.

tps is a likely suspect...throttle position sensor