green96ta

i did perform a leakdown test. i used 90psi compressed air. a local shop told me they thought i needed a colder plug, well they were wrong...

and its not a false miss, you can hear and feel it...

Injuneer

Always possible you have a lifter that isn't staying pumped up. It would tick though.

Is it possible you have the harness connector for two injectors swapped?

Gear Vendor O/D, replaces the tailshaft housing.

http://www.injuneer.com/images/photo.../DCP02954a.jpg

dangalla

at the point your at you have proved all else wrong, or at least you say you have. so here is what i would do...

step one- remove the spark plug, connect the wire to it and crank the motor to check the spark with it grounded to the block.

step two- remove the injectors and fuel rails as an assembly. with the fuel lines and harness connected have a friend crank the motor over. check the injector to make sure it is spraying

step three- remove the camshaft and check to make sure you dont have a lobe that has been worn down.

green96ta

i already have done all of that but pull the fuel rail and the cam, i pulled the valve cover and ive got good lift on that cylinder. with all my mods do you think that maybe it could be that i need bigger injectors? could i need a retune since ive deleted the egr?

green96ta

anyone else?

mrmint69

You haven't really done much to increase horsepower so they should be fine. If you switched injectors and the miss didn't follow it should rule them out. I haven't read all the posts but how did you determine it was the #3 cylinder?

93transam1234

ok i dont know where to go, so might as well go back to basics.
You need air,fuel, spark and comprestion
I know you have checked this stuff before but its time to double check

Sprak-Make sure your wires are connect in the correct order, llok up the info on shoeboxes site. Check the spak voltage or whatever (the best way to do this is to go ahead and let it shock you, then let one from a good cyl shock you, if its weaker you will be able to feel it)

Fuel-Check your fuel presure, Swap injectors, make sure you have the correct injector harness attached to the correct injector. Pull the injector and make sure it is fireing.

Air-CHeck your intake, is it possable that something sucked into your intake and is blocking the air inlet to that Cyl? Maybe bring the car up to operating temps and check the compresstion and do a leak down test possable its a warped head or gasket?

It has to be one of the above causing it, once youe figuare witch on it is (air,fuel or spark then it will be eaiser to find the root problem

dangalla

sounds to me like a compression issue, if i were you i would re check that, and make sure you are actually checking cyl 3

Chvywolf

The LT1 uses a reluctor wheel driven off the cam and a dual optical pickup to send timing information to the ecm. low resolution is cylinder specific information. 8 pulses, 1 per cylinder with differing pulse width to identify individual cylinders. High resolution signal is 360 pulses evenly spaced for accurate engine speed and a reference for cylinder identification. When the knock sensor detects a misfire, it uses the low resolution cylinder identification signal to determine which cylinder is affected.

This is the "opti" portion of the optispark.

I have run into problems before with the connectors for the opti being corroded and not sending an accurate signal to the ECM. I've gotten into the habit of putting a little bit of oil or shooting a little WD40 on electrical connectors.

green96ta

i guess i should get a new opti harness....its still got the factory one on there and the locking clip is broken. as far as how i know its cyl #3 i used my code reader. and i know which cylinder is number three. come on guys; give me some credit....

Injuneer

Did you check that the injector wires are on the correct injectors? You never really answered that question.

green96ta

yeah they are on the right injectors

mrmint69

Its possible the intake or exhaust manifold has a restriction. Theres a way to pass a chain through the passages to try and fix it.

Lt1son

Well ive read most of this and im sorry if i missed someone saying this...why not keep it simple..ever think of a plugged injector?...only cyl. #3..and all ur other tests have good numers?...if u can take it somewhere and have then clean the injectors or..just swap injectors and c if the miss follows it..just a thought..and once again sorry if someone said that already...good luck!

green96ta

i believe that this is my problem..when the plug on #3 does get fuel its not on all of the plug, just part...leading me to think that there is a restriction....since i have switched injectors