Now that the Alaskan mornings are below freezing my 97 Dakota 5.2 is showing it's cold blooded nature. It sat for 4 days and when my daughter went to start it in the morning she had a heck of a time keeping it running for the first few minutes. It would fire right off but would not idle to save it's life unless you stabbed the gas over and over to keep it from stalling.
I have cleaned the TB, new plugs & wires, now thinking the IAC or TPS need changing. Which should I change first? Or just do both? From what I've seen working on the engine so far, they are probably the original OEM Factory units from 97. The truck has 147K miles. It's getting pretty CRAPTASTIC mileage too. Around 10-12 if we are lucky. Should I just throw in a new MAP sensor while I'm at it as well?

 

might as well do the whole suite. Honestly, I'd blame the MAP before the other two.

 

Yeah I probably will. Thanks I thought the MAP doesn't have much to do with the idle on these motors?
Also the truck runs fine once it's warmed up. On an 88 Toyota pick-up I had there was a cold start sensor (like a choke) on the 3.0 V6 that would go bad and the same symptoms would occur.

 

It generally doesn't, but air pressure changes with temperature (density of air changes), and that mixed with a tight IAC means that it may be going lean. When it gets cold, air pressure at the surface increases as air molecules get closer together. This should tell the MAP to tell the PCM to put more fuel in the motor, which it may or may not. A sticky IAC will choke it off, so little air and little fuel = no idle.

In normal conditions, the MAP wouldn't overly affect the idle because the metering is already pretty much set by the TPS and computer programming. But if there's a significant weather swing, like going from 60F to 25F or 125F, the MAP will have a slight affect on the tuning window, and the coolant sensor will have a slightly bigger effect on it.

 

Nicely done Magnethead.
To the op I saw that you had already cleaned the TB. Did you clean up the IAC as well? Any buildup on the IAC pintle or in the TB in that area can cause problems.
just thought I would add that but it appears that you are in good hands.

 

Could be the IAC, MAP, or the O2 sensor. First thing I'd check is the IAC, because it's easy to get to and usually free to repair (just clean the pintle and seat.) TPS could be bad, too. Try aiming a heat gun at the suspect parts--you want to warm them up but not burn them.

I know, can't prewarm an O2 sensor.

Have you pulled codes?

Gotta ask, can you see Russia from your back porch?

 

No codes AND since that day it happened the truck has started up and idled just fine. With temps around the same. Must be something to do with sitting for four days??
AND NO I can't see Russia but on a clear day I can see Denali...