Rough idle in stop and go traffic

[KSpyder98]

So I have read a ton of threads on here about almost similar problems but haven't found any concrete answers so thought I would try my own. I recently bought a 98 Spyder with the 2.4 and have been working to fix it up. I changed all the fluids, put new spark plugs in, new o2 sensors, new air filter. My problem is that after driving for a bit and then getting stuck in stop and go traffic or a lot of lights, anything where the car isn't moving much, the idle gets all erratic and sometimes the car will stall all together, but then start right up. I am thinking that it has something to do with the heat because air isn't being forced into the engine bay by driving forward. The engine is stock except for a short air intake that ends with an air filter in the middle of the engine bay.

Since it is not shielded from the engine at all could this be causing my problem when no cold air is blowing into it? It has done the same rough idle and stall on occasion in the morning after I first start it up, more so if I haven't driven it in the past few days, which is a bit random and just confuses me more.

Anyone have any ideas??

Thanks a lot

EDIT: Very interesting new development, had it in the driveway with the hood up while it was hot out and after I had been driving it around. I noticed that it would bog down and then stall any time the passenger side radiator fan came on. I unplugged the fan and the stalling problem went away. It did not stall when the drive side fan came on. The battery is about five years old. Had a multi-meter on the battery while it was running, it was at about 13.7 volts but then when the fan came on it would dip down to under 13. Connected my battery with another one to give it more juice and when the passenger side fan came on it acted like it was going to stall but barely didn't.

I am planning on getting a new battery, is there any reason to get a new fan too? Could it be shorting out or something that is drawing more power then it should and bogging the engine down? Out of curiosity and wanting to learn more, why is low power killing the engine?

 

[Turbosnatch]

I doubt that ould be a problem because t's getting air regardless. have you tried fiddling with an idle screw at all on the throttle body, might raise the idle enough to stop it dying out

 

[KSpyder98]

I've thought about that but most of the time during normal driving the idle is fine.

Anyone experience this before?

 

[KSpyder98]

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Here is what it looks like. If the intake shouldn't cause a problem what else could it be?

 

[Tyeler18]

Any check engine lights on?

 

[KSpyder98]

Nope, no codes at all. I have Torque hooked up to a OBD2 bluetooth dongle to check for them.

 

[Bloody Panda]

Check your pcv valve. If its dirty it will get stuck shut and idle badly or even stall. Happened to me. Just cleaned it out and it worked fine.

 

[rydereclipse]

Temperature sensor? (not the instrument cluster one, the one that sends information to the ECU) In addition, check for faulty/cracked igntion wires (the wires that go to the actual coil pack, not the spark plug wires..although you shoudl check those too)

 

[KSpyder98]

Just checked the PCV valve, snaps shut when I put my finger over it while idling and then snaps back open so seems fine. I was wondering about the temperature sensor also, though I get a reading in Torque on the temp so it has to be working at least a little. How would I check to see if it is bad?

 

[curt-s]

Have you monitored the oxygen sensor? Does it properly cycle in closed-loop?

 

[KSpyder98]

I'm still in the learning phase, could you explain how I would go about that Sordid?

Thanks a lot

 

[KSpyder98]

Could the IAC have anything to do with this? How would I test it?

Thanks for any help, it is really annoying to have to constantly rev the engine any time I get stuck in traffic!

 

[KSpyder98]

Just discovered that it has to do with the radiator fan, anyone heard of this before?