engine miss

[kglowacky]

My LS1 swap has been great running for around 5 years. Yesterday I took it for a ride, and it developed a miss on acceleration and at all speeds. Got my mechanic coming by to place on a computer. The gas is probably 6 months old. Thinking of adding a additive the see if it is bad gas. Any suggestions on a additive? My guess is coil. donor car was a 2002 Firebird trans am

[Willie Makeit]

i'd bet a dollar to a donut if the fuel is that old it has a stuck injector. a quick ODB2 scan will tell you whether it's ignition or fuel related

[kglowacky]

Thats why I am thinking an additive may unstick it. Thats what I get for not driving it more.

[Accelo]

It's all speculation until you scan the computer.
An additive is unlikely to work unless the injector works partially, as it will never reach the injector.
Let us know what the scan identifies.
The self-diagnosis is way better than the earlier cars.

[leegreen]

perhaps loose plug wire or bad connection on a coil pack or injector.....with a seldom used vehicle, make sure mice have not been eating and peeing on your wires

[A1971Blazer]

Check first to make sure it's getting fire to each cylinder. I do this with an inductive timing light, just to see if it flashes on each cylinder.


Also check the connectors for both the coils and the injectors. When you turn the key to run position, they all should have voltage on them.

If all that checks out, then more than likely, you have a stuck(sticky) injector.

I first started my LS1, it had a dead miss, turns out it was a stuck injector.
My buddy also had the same issue with his 5.3, we pulled the injectors and two were gunked up and stuck.

[kglowacky]

Determined the issue is a bad injector. figure remove and replace/clean all of them??? NOW the question. New or clean them? Been looking back at this forum and most say rebuild/clean them. Mine are gray and I think org Delco. Thoughts.

What was the OEM Brand? Bosh

Wilie, I owe you a donut

[LS short box]

If it was me I would send all your injectors out to get cleaned and rebuilt. Good shops will supply a print out showing the flow rates on each injector.
Or just replace the bad injector with a OEM injector and then a bunch of injector cleaner?

[kglowacky]

My plan is I bought a oem rebuilt cleaned injector with a flow rate test included. Once I get it installed if all good, I will send out my org 8 for the same cleaning and then have a replacement one for backup.

[Willie Makeit]

Originally Posted by kglowacky

Determined the issue is a bad injector. figure remove and replace/clean all of them??? NOW the question. New or clean them? Been looking back at this forum and most say rebuild/clean them. Mine are gray and I think org Delco. Thoughts.

What was the OEM Brand? Bosh

Wilie, I owe you a donut

I've had good luck cleaning them myself. I run them thru my cheap Chinese ultra sonic cleaner filled hot soapy (dawn) water then "flush" them with a can of injector cleaner, a large livestock/vet syringe, a short piece of rubber hose and fire them with a 9 volt battery. Only ones I've ever had that didn't come back to life were because the solenoid was dead, not because they were dirty or gummy.

I have also used the plastic handle of a screwdriver to tap on the sticky injector while the engine was running to "persuade" it to unstick. Works better than you think.