Check engine light rough idle at start.
 

I’ve been reading through these forums for years and just now created an account. I love my Dodge truck and really enjoy working on it. But I’m no mechanic by no means.
I have had some issues with the CEL coming on and having a hard time keeping it running at first start. The light stays on all the time and it runs fine after a good warm up. But I have to keep peddling it until then. Trucks got 208k on it. I’ve apready been through a rear end swap, a 46re rebuild , and front end issues that I’m still trying to get a grip on. This truck is my daily driver with a 5.2l 318 2wd extended cab. I have done all the work myself from YouTube videos and these forums. Any help is much appreciated. I could take it to the shop but that’s no fun. Thanks y’all.

First step is to retrieve the error codes. Your profile says it's a 98 so try this: Start with the ignition off, then do on-off-on-off-on (ignition only, don't crank) and the odometer display shows a sequence of P codes followed by "done".

So no diagnostic tool needed huh? I’ve been a little reluctant to take it to autozone. Thanks for the info. I will try that.

Key dance is supposed to only work up to 97.
http://dodgeram.info/Engine-Gas/OBDI/pcm_fault_code.htm

You can buy a code reader for less that $20 these days. Best tool you can own. Then you don't have to guess.

Not to mention most auto parts stores will read codes for free.

The link refers to the pre-CCD bus systems. It does work on my 2001 2500, also on my 2003 Wrangler and a 2007 Grand Cherokee.

Still nothing.
 

Hey guys sorry it’s been a while. I work comm. HVAC and our hours are crazy. I tried the key test with no avail and I took it to autozone and they ran a diagnostic. Code P0505 Idle Air Control System. I tried cleaning the IAC and still no different. I can purchase a new one and try to reset the code. But I’m afraid I have a plenum problem. I’m loosing coolant and also have brown dirt like substance in my radiator. I need some pointers on flushing the coolant system and how to properly refill. I just purchased a complete ‘00’ model this weekend for a parts truck. It has a 5.9l in it but damn near the same truck. Thanks guys.

What year is your other truck?

P0505 won't have anything to do with the plenum. That's the computer telling you there is a problem with the IAC control circuits. (it is commanding a change, and not seeing it.) With the engine at idle, unplug the IAC, test all four wires for voltage. You should see 12 volts on TWO wires. if you don't, it's possible the PCM has taken a dump.

2000 with the 5.9l. Is that going to have the same PCM?