Is you Knock sensor taking performance down for the count?

[XfireZ51]

The Service ASR light will come on when in ALDL mode. So if you connected your scan tool, you'll see the light. The Service Ride Control will light if you've started the car 3 times without moving it.
Does the vacuum pump come on when you turn ignition "ON"? It's in the front passenger side by the coolant overflow "bottle". It should only run for a few seconds. If it continues, there's a vacuum leak and will affect secondary operation. With your scan tool I would check all sensor values with ignition "ON" making sure they are within range, like TPS, MAP etc. Check hoses like the PCV connections and the MAP sensor.
Have you pulled plugs and how did they look?
I know this sounds basic, but from our perspective here, it helps to understand the baseline condition of the car before speculating on what's going on.

[Tyler Townsley]

Check to see of both pumps are working. Many times falling on its nose on hard accel is cause by the secondary pump being bad. OE pumps do not like sitting for long periods of time and also do not like running with the tank lower than 1/4 tank.

Tyler

[Vettetech1]

See that's what I was wondering I know this car sits. When he came to pick it up it was sitting on reserve with one bar left. Per my boss I just pulled the plenum to recheck the injector ohms 12.4 to 12.8 across the board. Is there anything else I should check while under this damn plenum. Also what is the failure rates of coils and the module on the underside of the plenum.

[Pete]

Knock sensor is the correct unit and ohms correct.

You need to look at common issues on this forum.

Just a couple that come to mind with the issue you are having is wires and injectors.

Injectors can ohm good and still be bad check for leaky injector before you go changing fuel pumps.

Pete

[Vettetech1]

Originally Posted by Pete

Knock sensor is the correct unit and ohms correct.

You need to look at common issues on this forum.

Just a couple that come to mind with the issue you are having is wires and injectors.

Injectors can ohm good and still be bad check for leaky injector before you go changing fuel pumps.

Pete

Thanks Pete that was my biggest concern was the knock sensor ohms. I got the upper off and don't see any fuel dripping from the injectors. Seems to hold fuel pressure on the gauge and run in spec. Car ran great after injector replacement but now has a miss, almost like a cracked plug. Seems to idle nice. Pulling plugs now to see if i can see a odd one but so far they look pretty good. Back to the drawing board.

[Tyler Townsley]

Originally Posted by Vettetech1

See that's what I was wondering I know this car sits. When he came to pick it up it was sitting on reserve with one bar left. Per my boss I just pulled the plenum to recheck the injector ohms 12.4 to 12.8 across the board. Is there anything else I should check while under this damn plenum. Also what is the failure rates of coils and the module on the underside of the plenum.

If the tank was that low it may have picked up some not so good gas. Try some injector cleaner and a run through a tankfull of gas. To check a plug miss I pull the plugs and put the boot on, lay them on the plenum and crank the car, all plugs should show the same spark color/intensity.

To check for fuel flow look at the plugs when you have them out to make sure they are all the same color. Check by switching the plug to a good cyl and see if the plug 'cleans up' and the other has change color. If its black leaking inj if its too brown lean condition/bad plug.

Tyler

[Pete]

Just a thought.
Please don't tell me you used Bosch spark plugs or some other expensive fancy name plugs.
If so take them out and replace with a resistor plug.

I like to diagnose from cheap to expensive.

Pete

[Vettetech1]

Originally Posted by Pete

Just a thought.
Please don't tell me you used Bosch spark plugs or some other expensive fancy name plugs.
If so take them out and replace with a resistor plug.

I like to diagnose from cheap to expensive.

Pete

I hate Bosch, Champion, Denso, and NGK. I know some people live by those plugs but i have never had luck with them. This thing has only got 23000 on it, never beaten original tires (which blow by the way they are so damn hard and slick). It still has the OEM Delcos in it which are as clean looking as the day it left the factory. Think I found the problem, just waiting on plenum gaskets so i can put it back together. Think it is my fault, I didnt realize when i pulled the upper to do injectors i had some coolant get down in the #8 spark plug well. I think is was causing a high moister issue and i think the spark was jumping through the boot. So I dried it out checked plug gaps. (customer doesn't want to replace them yet) and we have a good set of take off LT5 wires im gonna snag a #8 wire. (Maybe pray to the car gods) I'll let you all know how it turns out in a few days.