I will be interested to see what you find out about this condition - to me, it seems unlikely that it is a spark plug wire issue so much as an issue with the idle circuit. I would not expect a spark plug wire to only miss every once in a while. When you say that your IAC is going up - where are you seeing that? Is the IAC going up preceding this event, or after it has already started?

Most of what I see in this log seems to be a reaction of the FI to the low idle event - nothing is jumping out at me as a predecessor. Your MAP sensor shows you losing vacuum (getting closer to atmospheric pressure) just following the event, which (if I had to guess) is likely caused by your IAC opening up and introducing some extra air into the system to induce a vacuum leak and increase idle RPMs in reaction to the dip. Similarly, your Inj_PW increases to feed more fuel into the system to try to get it to recover.

Is it just me, or does it seem like there's a lag in MAP response compared to earlier in that log (to the left), where any brief dip in idle yields an immediate MAP increase? Hard to tell without a grid.

At any rate, in the past I have had an almost identical issue with my Powerjection unit, which turned out to be an IAC issue. An unfortunate problem with my particular TB is that the IAC can't be removed for cleaning, so the best you can do is shoot some carb cleaner down there... which works, kind of mostly. You might try cleaning yours if you can to see if that helps.

I use Taylor wires and they have been excellent for 5 years now.

 

When you say that your IAC is going up - where are you seeing that? Is the IAC going up preceding this event, or after it has already started?

the IAC is going up while the RPM is dropping - attached is the full log https://drive.google.com/file/d/1EggLQn--OIUu_x8YxFeqmytofl3Au8iV/view?usp=sharing

 

I followed a thread on another forum where a fellow had all kinds of intermittent problems getting a Holley Sniper to run right. What he found was


"The issue with the Fox running well has been identified - basically the Sniper cannot wear a metal air cleaner that comes anywhere close to the distributor. The issue is further compounded by the fact my dizzy is 1.25" taller than a stock dizzy, and, the stock Ford air cleaner is very large. In combination these two items seem to somehow cause the ECU to completely reset while running making the car extremely difficult to drive. So, I have ordered a shorter dizzy and will use a plastic K&N air cleaner for the time being."


As far as plug wires - I like the make-your-own Taylor setup, in conjunction with really good separators - that way you can make them just the right length. I find the the separators that bolt in place of the valve cover bolts work really well at keeping the wires separated.

 

I second the Taylor recommendation. The set I bought had the spark boots attached. I had to cut the wires to fit and attach the distributor ends myself; no big deal.

FYI, I have old Jeep pickup that had a lousy idle. I fought the problem for years. I installed a few sets of new spark plug wires and the problem persisted. One night I popped the hood and saw blue arcing and sparking all over the place. It occurred to me I had been buying the store brand plug wires. I went to NAPA and bought their best quality set of spark plug wires. No more arcing and sparcing and the idle problem went away.

I don't know anything about your Holley Sniper setup, but cheap plug wires can definitely cause idle issues!

 

I have had great luck with both Taylor and MSD wires. I use a lot of separators.

 

does bigger = better with spark plug wire thickness? 8mm seems to be the norm -

 

Look at FireCore wires - look them up. Mopar guys/drag racers swear by them. They are the best. A named Rick Gorsky is the man. You will not be disappointed,


Dean

 

so this kit?

FireCore 50 Wires Pro Fit, HEI

 

I used Ford Racing wires for several years but fought a problem with them coming off of the plugs at random times and plugs. About a year and a half ago I switched to MSD wires. No problems since and they seem to be working fine. As with any plug wire, ya gotta keep them away from each other and from metal as much as possible.

Gary

 

I'm using these; https://www.bluestreakwire.com/Default.aspx The 9mm ones.

 

I went 10.03@136 mph with a $20 set of O'Reilly Omni-Spark plug wires....

Would I have gone faster with different wires ? I doubt it....

Use a good distributor and a good coil and the wires aren't so important IMHO.

 

thats what i would think too - but in terms of daily driving im trying to get my EFI to run the smoothest, so the wires are a likely (and hopefully) culprit of my idle issues (have a new distributor and coil)