About a year ago I put coated Pacesetter Lt's on,removed cat, put a single Magnaflow polished dual in dual out(w/internal x) muffler. and all new mandrel bent tubing. Since that day I have had idle problems. At first,day(s) after install I had major idle problems. The truck was basiclly in limp mode. The idle was reall jacked up jumping up to 2k rpms etc.... After checking for pinholes in the new exhaust and having them professionally fixed nothing changed.

We then started focusing on the o2's. My buddy had my stock ones replaced with some new ones under warranty(hehe!). This basiclly did nothing. So I came to learn that alot of the LS1/car folks were fixing this issue with 2002 Vette rear o2's because they heated up better and faster as well as had a faster switching rate. So I picked some up and installed them which sucked becuase the connections were way off. Had to do some splicing! Yuk!
Once installed my major problem of basiclly being limp and loaded up beyond belief was now fixed. I still had a small problem compared to the other of my idle fluctuating. It was worse when parked but still did when in drive/reverse. It was also worse when the ac was on. So for a year now this has been going on and Ive learned to love with it.
Well now I am all caught up and want to get this problem fixed once and for all. My buddy was making some adjustments to my tune since he just got a wideband and I just installed a convertor. So we are now trying to fix the idle problem. Its not a uniform fluctuation either. Its all over the place.Back and forth back and forth. The highest it will go is around 1500 rpms but it is extremely annoying. Well last night we were scanning in idle,making adjsutments, and clearing a fuel bank rich 1 & 2 DTC we started to think this idle issue has to be o2 related. While in park we would bring it up to 2k rpms and hold it for like a minute or so and let off. Each time we did this after letting off the rpms would level and not fluctuate for a minute or two and then start back fluctuating.
The o2's are about halfway up the collector. We are starting to think that moving them back about 4 or so inchs(to the end or close to the end of the collector) may be the fix. It doesnt seem like much but I dont know what else to do. It seems like and its only been a day that my buddy some how has the rpms level when the ac is off. He raised the idle. Regardless of that does anyone have any ideas? Could this have anyhting to do with RAFIG/RAFPN ? Any ideas would be appreciated and useful.

 

I think you answered your own question. Sounds like RAF, If your not sure its correct? it may be a problem.

 

OK my problem may be fixed and I think it is. I did the new exhaust(coated Pacesetter LT's,dual in/out polisged 22" Magnaflow, removed the cats, and mandrel all the way around) over a year ago. At the time the turndowns that were ordered hadnt come in. So i was to go back to my then perf shop to get them put on. The hting is that a sort of failing out happened with me and that shop. I said screw it Ill get some turndowns put on later.
Well it got put on the bottom of my list of things to do and that was that. No biggie. Well I now am at the point were Im trying to take care of alot of the small things and go on to bigger things. Cough**turbo**cough!
So this idle fluctuation is what Im on. It has been there since the new exhaust. It didnt affect the performance of my truck it was just a nuisance. I decieded to move my front o2's back about 6 inchs to maybe get some better readings and maybe be the fix to the idle problem. So I went to get two new bungs put in(I am going to move the o2's myself) and another bung for the wideband. I also had them put some turndowns finally.
I get my truck back and obviously its quiter but the idle problem seemed to be gone!!!
I go to my buddies work who also does my tuning and he says"oh its just becuase the o2's are nice and hot from the tubing being welded" OK maybe but not after a hour and definetly not 4 hours later. He now says that it could as well be fixed! So I ask you was it possible the o2's were getting bad readings when at idle because of this setup? I dont know the physics of this stuff but it sure seems to be fixed!