Misfire Update

[Eastcoast SHO]

Ok so it has been approx. 3 weeks since i reinsulated the cp wires as suggested by a few members here.

Here and there I have been driving it, and it has at the very least 30 cycles

No misfire code

the only codes i still have are secondaries staying open and front bank running lean

The only noticeable issue is the idle. sometimes it idles perfect other times it jumps like a sob, especially if i am at a red light it jumps goes up and down like crazy not too too bad but within 200-400 rpms each way,sometimes like it wants to die then wants to move. could this be caused by the front bank
o2 sensor?

I dont think i have a misfire anymore it hasnt showed up on the code reader

any ideas?

 

[Bob Gervais]

The jumping idle sounds like a MAF or vacuum leak issue. Hook up a vacuum gauge and see what it reads, I'm not sure what the average V8 reads, but look for a steady needle. A steady low reading will be a vacuum leak, jumping needle would indicate ring/valve issues.

Maybe clean the MAF too, and see what happens.

 

[Eastcoast SHO]

The first thing i did was clean the MAF, no difference.

I am almost positive(I say almost because maybe I did miss something) that there is no vacuum leaks as that was another first i looked for

btw if i were to do a vacuum test where would i hook it up?

 

[Bob Gervais]

You can hook the gauge up to any vacuum line. Just make sure you plug whatever port you pull the vacuum line off of, so you don't create a vacuum leak. Autozone and most parts stores have vacuum caps that come in a box with a few different sizes for a few bucks. I think AZ also rents a vacuum gauge, and sells an inexpensive version. It's a pretty handy tool to have.

 

[Eastcoast SHO]

hmm...i will have to look into that, thanks bob

 

[jmpSHO]

The first thing i did was clean the MAF, no difference.

I am almost positive(I say almost because maybe I did miss something) that there is no vacuum leaks as that was another first i looked for

btw if i were to do a vacuum test where would i hook it up?

Just because you cleaned the MAF doesn't mean it is good. Sometimes they go bad and cleaning won't help at all.

 

[Eastcoast SHO]

Just because you cleaned the MAF doesn't mean it is good. Sometimes they go bad and cleaning won't help at all.

never thought of that, how do i know its bad? replace it with a known good one and see if it goes away?

 

[Bob Gervais]

never thought of that, how do i know its bad? replace it with a known good one and see if it goes away?

Yep, that's the easiest way.

 

[Mr Anonymous]

The only noticeable issue is the idle. sometimes it idles perfect other times it jumps like a sob, especially if i am at a red light it jumps goes up and down like crazy not too too bad but within 200-400 rpms each way,sometimes like it wants to die then wants to move. could this be caused by the front bank
o2 sensor?

That's a misfire.

 

[stephen newberg]

That's a misfire.

I agree. I think your problem is misfire. It can take ages for that to throw a usable code.

pax, smn

 

[jmpSHO]

I also agree with everyone else that you still have a misfire. On my old Gen 3 I would have to drive almost 600-700 miles for that code to appear.

 

[Eastcoast SHO]

WTF? This sucks, i just wish it would show up, because when i reinsulated the cp wires i moved around the coil packs, to see if the misfire has moved

 

[BamSHO]

I have a 97 Expedition with the 5.4 and its the same way. Takes forever for the CEL to come on for the missfiring cylinder. Ive changed out 5 packs now. I know it sucks.

 

[three50one]

Mine never showed a misfire and I drove it for a long time. Changed all of the coils and plugs and my issues are gone. I got the "cheap" set of 8 off the guy on ebay.

 

[Ian Macoomb]

If you've got a code reader and the car is acting up, sometimes you can get a pending code by putting it in 2nd and flooring it from a stop. I got a few codes that way with my trusty Equus code reader. And it's ancient. I've had that for about 6 years.