MarcR94v6

So for the last 5 hours or so I've been.... reading numerous otvc threads, low rpm stumble threads for the past several weeks, and had my finger on the buy button on summit racing.

My problem will sound quite familiar - flat spot/stumble at 2,000-2,500 rpms, will miss occasionally during this time (intake backfire - cough sound), especially under load (up a hill). I can push through this wall, but will often end up back behind it at the next gear. It usually doesn't happen untl closed loop, so I am thinking wires getting too hot, maybe even burning. My preferred shop ran a number of tests, put it on the dyno, test drives, ignition scope, etc. They could not get it to miss, nor found any porblem with the ignition system.

Now though I have shorty headers, on the passenger side mostly I see a few areas at the bottom by the 02 sensors, though zip tied well, are too damn close to the primaries. So this could be my problem, and I plan to do otvc top mount with boot protectors for added protection. I really wanted to do side mount because I am modifying the stock valve covers to look a little more sharp, but side mount is just not far enough away from the headers and would defeat the purpose. The wires I have on now are stock replacement wires (random napa wires). So I'd like to upgrade anyhow.

Problem is, I don't make a lot of money (quite underpaid) so I can only tackle one potential solution at a time. so the question is, is this a potential solution?

btw - would 1200* heat protectors be enough protection?

Other upgrades that could solve this that I have planned:
-bigger injectors and 255lph pump (getting close to passing 350 flywheel hp with 1.6 RR and tune, hell I'm likely at it now)
-various sensor replacements - tps, lt4 km, iac
-replace battery (because of one thread on cz28 about it)
-opti (why not, the one on it is from NAPA)

Thanks for reading the 673rd thread on two widely posted subjects.

CGrant

I have the ovc wires and am very happy with them, sounds like you probably just need a tune up?

edit, just re-read your post and my car did the same thing (backfire) when i 1st got my car back together from the 355 build, ended up being tuning issue, got it re-dyno tuned and it was fine afterwards. looks like you have a 357, not sure how long ago this started?

MarcR94v6

Actually on and off right after I got the car back from being built (5k miles ago). first it was oil dripping onto ignition parts. The leak was fixed but the problem for a while but it still comes back on and off, very inconsistent at times. Dyno tune is about $800 for me...way too expensive, I'll try a mail order madz28 tune, thanks for the tip, didn't think about that, maybe some timing needs to be cleared up by a tune. Actually, now that I think about it.....the oil probably only caused the belt to squeak annoyingly, the problem I have currently was there from something else that is yet to be determined.

I also noticed, it's inconsistent off idle. Right after my 54MM tb install, it pinned me back in my seat at every throttle application. Now it mostly is just slow off idle.

klrz28

is it hard to crimp your own boots on any secrets ?

Rising Phoenix

If nothing else they look really good

MarcR94v6

Don't know, I'll find out this week, lol.

I went with the side mount because I'm doing something special with the valvecovers but am using b01200* oot protectors too just in case.

I guess from Phoenix's pictures, I'll be removing slightly more than I thought I'd have to to really get in there. Oh well, I planned to take a few days for it anyway.

MarcR94v6

Is it at all possible that a dirty IAC valve could cause flatspots/stuttering? I cleaned mine and they problem hasn't been back in a few days....then again it has cleared up before without reason.