Hi, I just did a compression test on my motor, cuz i thought the valves weren't seating. I got 175-180 pounds across the board. (Thank ***) SO then I went to autozone and bought a noid light for the injector harness, each one blinked while cranking. THen I bout a spark checker and attatched it to the end of each wire, got strong blue spark on every one. Tested the fuel pressure got 43-44 lbs. Ive eliminated all problems to either the injectors or the plugs.

Here's the plan, get some bosch platinums, and then test the i njectors by removing the harness at each one, and see if the idle changes.

DOes this sound like a good plan?

edit: There are no trouble codes, i have fixed each one. I only had to replace maf sensor, and egr valve.

 

Er....what's the problem?

 

oh yah, it has a bad misfire it seems, and it has a lopey, shaky idle, **** poor throttle response. should be the complete opposite of lope with the stock cam.

 

Prety much the same problem I am having. I am trying to read as much as I can and do some searches about this problem, but am still searching at this point. Sure hope there are some educated people that can educate me .

THANKS IN ADVANCE FOR YOUR ANSWERS!!!

 

I know what your talking about I have the same problem too. now i know a Haynes manual is'nt the greatest resource for troubleshooting tips but.....it does say some interesting things.
one of the main things being, check for vacuum leaks. I know that is a good place to start. You've made now mention as to whether or not that you've done the vacuum leak test. Which is nothing more than spraying starting fluid, or carb cleaner on the vacuum lines, and listening for a increase in idle speed.You could also do this with a spray bottle of soapy water and look for bubbles,or a stethascope, or a peice of fuel hose and listen for hissing.
Another thing is, have you cleaned you IAC? If not you should anyways, even if it does'nt solve the problem, along with setting the idle speed and the TPS voltage. That might cure some of the throttle response issues.
I have yet to go through all my vacuum lines, because I am going to replace all of them with red silicone vacuum line from Eastwood company.
So how many miles does the car have on it anyways....? And is the drivability problem through the whole RPM range or just an idle, off the line stumble?

 

hey,

I've checked all sources for vacuum leaks with throttle body cleaner, including vacuum lines and the intake manifold. Eliminated one leak from a line byreplacing it. I have also cleaned out the iac valve and passages. I need to set the minimum idle speed, but i don't think it will idle at 450 rpms, the tach jumps around like crazy. i don't think its running on all 8 cylinders, either because of bad spark plugs, or bad fuel injectors. The thing that bugs me though, is that i got the injectors cleaned, and i measured the resistance of each of them and it was in specs, they should be fine, am i right? And also, the wires, cap, rotor, distributor, and coil are fine because i just checked teh spark at the end of each wire.

One thing i was thinking about is, could having the wrong heat range spark plug cause this? I have vette heads on it, but am using spark plugs for a firebird not a vette, and i know that since the vette heads are aluminum i need a different heat range [plug. It doesn't seem that this would create so many problems.

I know I;m getting spark, and i know I'm getting the right amount of fuel to the injectors via fuel pressure test, and i have good compression, it seems to me that fuel air and spark are all togethor here, its just the man upstairs hates me or somethin.

 

did you check your EGR?

 

The plugs for the cast iron “Firebird” heads have a .460 reach (thread) with a tapered seat (Autolite #26) and the aluminum “Vette” heads require a .750 reach (threads) with a gasket seat (Autolite 3926). With the "firebird" plugs, the electrode is sitting inside the spark plug hole (as opposed to the chamber) and you're probably not getting a good seal at the plug opening. Buy a set of plugs for the Corvette heads.

 

I don't know if headers were mentioned as far as clearance is concerned but as far as the spark plugs go, Kevin is correct. You will need a 14 mm gasketed plug with a 3/4" reach.... old ACDelco fr3ls (this number has been replaced though).

 

You said you checked your sec. ignition but I am thinking about spark plug wires anyway. You could have a bad wire or two. They could still send a spark through to the plug AND visually look okay, yet be bad. Maybe worth looking into again...