Originally posted by BlackPantherSVT:
EdorFox, you mirror my sentiments exactly down to a T. I have an update. I got the same results as Edor on the secondaries tied, seemed to make it worse. Warmonger, I wanted to confirm one thing. I can be stuttering like a mofo - but if I throw it into neutral with no load, at same rpm and throttle position = BOOM stuttering gone instantly. I ONLY stutter in gear under load. Are you the same way? I am now going to try and get a new ign module and coil pack and new wires. Wtf, why not. I already bought 9mms, but if my pack is messed - it fried em too. Maybe. It worked for BlackCoog, shrug. Hey Coog, is your MaF connected to the throttle body in a stock fashion? One thing for God's honest truth, I am going to get a new O2 bung welded in and get a wide-band 02 put it; run it into cabin to a gauge. This way I can see if I am running lean or rich during the stuttering. If I run rich, its ignition misifre = not enough spark = unburnt fuel. If I run lean, = not enough fuel and too much air = fuel delievery in some fashion. Then I will know for sure. Bleh. More later, as always.
It is common for a misfire to only be noticeable under a load.
This indicates one of three things:
1.)a rich condition where too much gas is fouling the plug.
2.)a lean condition with not enough gas for proper combustion.
3.)insufficient spark to ignite the mixture.
It sounds to me like you should pursue the following avenues:
1.) Verify the condition of your ignition coil as I outlined in the above post.
2.) Check the condition of plugs and wires. Look at the plugs to see if one is discolored (lighter ~ lean) (darker = rich). If all the plugs look good and of the same color then there is probably no problem.
3.) Check the resistance on each of your fuel injectors. This may sound funny, but it is obvious that all of them are firing and not plugged up if you are running good at high rpm full throttle. However, if the resistance of one or two injectors is not the same as the other injectors, then at low duty cycles (low "on" times) you will get different amounts of fuel. For example:
If the normal resistance is 14 ohms for the injectors, but you find that injector # 4 is now 10 ohms; then you will be dumping a different amount of fuel in cylinder # 4 at the same duty cyle. It might only be a slight difference, but it could be enough. If the resistance is higher, 16 ohms or so, then at low duty cycles the injector would be less likely to open as effectively.
In the end, if fuel is good, spark is good, and air is good, then you have a pcm or sensor issue.
That should be enough to get you started, Good Luck.
warmonger
