Misfire! WTF?

[twinz1]

ok so i have done research for everyone thats about to say look up the topic lol

it all started when i pulled my injector connectors to clean some corrosion off of them , ever since then its been misfiring, and this is what ive done so far but its still misfiring? and its a bad misfire

-Bought new injector connectors and installed them to replace the old and corroded ones-checked all the connections to make sure it was tight-checked all my ignition connectors to make sure they were tight and not corroded too-my coolant temp sens is workingchecked to see if my injectors were releasing ( the click noise with a screwdriver)-ohm'd out the inejctors and they all read between 12-14 -unplugged connectors for a change in idle and found in 1 of the ignition connectors wasnt changing idle at all so i swapped it with another ignition coil to see if it was a bad coil but it stayed the same for just that cylinder so i checked the spark plug and there was alot of carbon buildup on it and the tip of the plug didnt have any white powder crap looking on it so it seemed like it wasnt sparking so i changed the plug and its still misfiring, so then i looked at the ignition connector and the wiring and its fine bc i took the multimeter out and im getting voltage thru it....

idk what else to do? can anyone help me,,, the car was running fine until one day i decided to clean the connectors a little but to free them up from corrosion a little but as soon as i got done and started the car up it started misfiring... whatttt cannn i doooo im gonna bring it to a mechanic tomorrow but wanna know if i can do anything to save me some money

[evildky]

so the injectors are good, you've verified that the cop and the plug are good, have you verified that you are getting spark at taht culinder? have you checked the ecu for codes? you might have a bad ptu, you can lay the cop and plug ont eh plenum and take otu the cas (mark it's location first) they rotate it and look for spark from that plug, if you know that cop and plug are good but get no spark then you have a dead channel ont he ptu

[twinz1]

i did the cop and plug test and i do have spark , im pretty sure its the injector so im gonna buy a new one and try that out..

[robomatic12]

I would definetely check for corrosion on the PTU conectors, I dropped a cylinder and the PTU connectors were green full of corrosion. Cleaned them up and applied electrical grease and it solves the problem for the future.

[Zwicked]

Pull the CAS connector and see if it is clean as well. A poor connection at that point can also cause misfire.
Modified by Zwicked at 6:34 AM 11/14/2009

[nightops]

Pull the CAS connector and see if it is clean as well. A poor connection at that point can also cause misfire. Often that will show up weak turbo seals and it almost always shows up only on deceleration or when you come to an abrupt stop and let off the throttle.

so you're saying that the CAS connection can cause smoking on decel like bad turbo seals?

[ztommyx]

make sure your spark plugs are gapped correctly w/ correct spark plugs. most misfire are caused by spark plugs.

i'm sure one or two of your plugs are bad.

[Zwicked]

HAHA, no I was in the process of editing another post and pasted something into the wrong post. The CAS part is right, the smoke part was not.

[Ampstunner]

91 300ZX Twin Turbo new injectors new spark plugs coil packs are not bad the car out of up and down 3 5 misfire