Misfire on #1

**INeedLS1** · 04-21-2007, 08:12 AM

I have a misfire on #1. It seems to only happen during the first few minutes after I start the car either hot or cold. How can I tell if it is a plug, wire or coil problems?

**Steve Crowe** · 04-21-2007, 08:47 AM

Try swapping the coil with a different one to see if the problem moves.

Remove the plug and inspect it for hairline cracks in the ceramic insulator.

You can ohm out the wire but that's not always accurate.

If the problem persists chances are you've got a gummed up or otherwise failing injector.

It's a good idea to try a profesional injector cleaning before replacing an injector. We sell a kit that close to the price of a single new injector which can not only be used to clean all of yours but it can be re-used over and over again on as many different cars as you like.

**jigger1166** · 04-22-2007, 07:00 AM

Originally Posted by INeedLS1

I have a misfire on #1. It seems to only happen during the first few minutes after I start the car either hot or cold. How can I tell if it is a plug, wire or coil problems?

If you're certain it's cyl. #1, you can swap the - coil, wire, plug, injector, with another cyl., one at a time 'til you find the problem.

**Rivi** · 04-22-2007, 06:30 PM

might be valve seals.very common cause of misfires on starts that gets overlooked.if the intake valve oil seal leaks a little when the engine is off the 1st thing the plug gets is a squirt of oil that will cause it to misfire until it burns off.sometimes the guide is worn too.if the guide is worn it will wear the new seal too.to check this do this test,start the engine and as soon as it starts to miss turn it off.pull the plug and check to see if its oil fouled.if it is its the valve seal.if its gas fouled it could be the injector,pcm,wiring or plug.i'm betting its oil fouled.

**SeVeReDiStOrTiOn** · 04-22-2007, 06:44 PM

Pull the plug and see what's going on...is it fouled? Check for spark...pull the wire off the plug, put a screwdriver across the end and ground the screwdriver. Crank it but don't start it...check for an arch. If you get spark and the plug is ok you can swap and pop the injector...could also be a valve seal like Rivi said