Idle Problem with X not urgent but please help!

[beast]

Today my X started a weird idle problem. At a stop, it idles fine for 10 or 15 seconds, then dips to about 400 RPM and feels like it is dying, and the lights dim and the battery power gage dips, then a few seconds later it pops back up to almost a 1000, jolts a bit and the lights come back. Then it will level out to normal, and do the whole thing over again. It still drives perfect. I recently installed a BBK TB and ifab.net intake, but it has been in there for 2 weeks no problems like this until today. I am still using my old KKM filter, could a dirty filter cause this? Any other thoughts? Thanks.

 

[beast]

bump

 

[MrShorty]

Dirty IAC valve is a common cause of this kind of issue.
An intermittent vacuum leak or a leak at the recently replaced throttle body might do this.
A loose connection at the TPS might cause similar issues.

 

[beast]

Ok, so today it didnt do it at all until I turned on my defroster. So the problem only occurs when the air is on it appears. At first I thought maybe it was the alternator or battery going bad because right as I turned the air on it does it, but I also had on the stereo/sub, seat warmer, wipers, and lights. But I turned all those off and it still does it. So the defroster is the cause, does that lead anyone to believe that it may be on particular thing.

 

[beast]

Basically, when I turn on the defroster, it nearly kills the engine.

 

[beast]

any more ideas on a specific cause?

 

[jnealg]

as was said... probably a bad IAC.. do a search and see if those symptoms fit. Mine has the ghost in the machine symptom but I'll let it run for a while till it gives idleing probs.

 

[newbi]

Measure the battery current with a voltmeter. Should be around 12.5-13.5 VDC depending on your battery condition and ambient temperture. Then start the truck and recheck voltage at battery. Should be charging at around 14VDC. Not charging=altenator or connections, low intial battery voltage=battery

 

[beast]

ok quick update on exactly what is happening - When I idle with the air on (a/c, defroster) the RPMs dip to about 400, the lights dim, and the power gauge drops from about 16V to 10V. As soon as I start moving again it jumps back up to normal. If I shift it into park and rev the engine, it goes back to normal for about 10 seconds and then dips again. You can feel the engine sort of die when it does it too. Occasionally it will jump back up on its own without me touching the gas, and you can feel the engine jolt forward, but it always falls again. The car drives fine, and idles perfectly when the air is not on.

 

[axionplaya]

check for the possible misfire... theyre cause by connections to the engine from variety of sources--- notably defrosting and a/c system. They might be burned or fried completely causing your engine to just simply drag when you turn either the defroster or air on.

 

[newbi]

Bet the battery is on its last leg from what you describe. Swing by your local parts house and get it(the battery) load checked.