Flashing check engine light

Hello my name is Dave.

First thing we need to find out is what code is being generated when this happens. here is a link to our tutorial on finding the codes:

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Keep in mind that the check engine light doesn't have to be actively on when you retrieve the code because the computer will store it. If you can retrieve the code and let us know what you find we will be glad to assist you in finding the cause. We look forward to hearing back from you and thank you for using 2CarPros!

Hello Dave.my obd says no codes are stored in the module.no pending codes are stored in the module.thanks

Hello Dave.I have 2001 buick century 3.1 had code po442. That car ran very poorly at one time with no check engine light it was the catalytic converter. Do you think maybe my catalytic converter on my truck getting hot when tromping on gas is causing my issue? Thanks

Hi Dave.

I finally got a code.it is po302.I drove it for awhile.my engine light started Flashing and I retrieve the code.thanks

Hello, this is Tom.

Here are the issues that can be the cause for your code it can be many things so we will have to go through to figure which is yours. Review this list of symptoms and causes and get back to us with anything that sticks out to you. Giving us an idea of how this began will help as well, things like any work done lately, Did this start all of a sudden or has it been a situation that was every once and a while that has becoming worse over time or have you gone to a different fueling station than usual. Pulling a spark plug to see it condition will give us good info on the burn and whether or not you due for a tune up.

Here is a good article for your review as well:

https://www.2carpros.com/articles/engine-has-low-power-output

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

P0302 Symptoms
Check Engine Light flashing
Rough running, hesitation, and/or jerking when accelerating
In most cases, there are no adverse conditions noticed by the driver
In some cases, there may be performance problems, such as dying at stop signs or rough idling, hesitation, misfires or lack of power (especially during acceleration), and a decrease in fuel economy.

Common Problems That Trigger the P0302
Worn out spark plugs, ignition wires, coil(s), distributor cap and rotor (when applicable)
Incorrect ignition timing
Vacuum leak(s)
Low or weak fuel pressure
Improperly functioning EGR system
Defective Mass Air Flow Sensor
Defective Crankshaft and/or Camshaft Sensor
Defective Throttle Position Sensor
Mechanical engine problems (i.e.—low compression, leaking head gasket(s), or valve problems.

Common Misdiagnoses
Fuel Injectors
Oxygen Sensor(s)
Powertrain/Drivetrain problems
Polluting Gases Expelled
HCs (Hydrocarbons): Unburned droplets of raw fuel that smell, affect breathing, and contribute to smog
CO (Carbon Monoxide): Partially burned fuel that is an odorless and deadly poisonous gas
NOX (Oxides of Nitrogen): One of the two ingredients that, when exposed to sunlight, cause smog.
Get back to us with what you have figured out
Tom

The truck runs good since I bought it at 90,000 miles. I had to put intake manifold gaskets on it they leaked. I never beat this truck just the opposite about 4 times I tromped the gas to pass a vehicle.3 times my light would flash and would run with a miss for a short time. everything good. the last time I tromped it the miss stayed. I got a code.no 2 cylinder miss. I checked my compression in# 2.it has zero compression. took valve cover off the right side where# 2 is. the valve train looks good moving up and down as it should. triple checked compression still at zero psi. I did tap lightly on top of valves with hammer to maybe loosen something up with no positive results.# 2 cylinder still zero psi. do you have any suggestions where I should go from here? thank you!

I stomped down on gas pedal for a little time going up hill to pass vehicle.now my truck is missing.I have code po302. any suggestions? thanks

The first thing I would try is swapping the plugs from cylinder 2 to one next to it. Or if the plugs haven't been changed in a while change them all. If the misfire goes away you're done. Next would be to check the wires and cap for any damage or carbon tracking. If none of those work then the next most common issue would be a stuck injector poppet on the "spider" injector inside the intake manifold. The last item is one that seems to happen on the 4.3's when pulling hard like going uphill with your foot to the floor is that the exhaust valves can bind in the guides and cause a misfire. Usually if this is the reason the misfire will go away once the engine load drops off and it runs at a lower rpm for a bit. If your misfire is still missing (not just showing the code) then it is more likely the plugs or ignition parts. For the injector a heavy dose of seafoam cleaner in the gas might help free it, especially if you have been running ethanol gas for a while.

I did complete tune up last year. this last time when I tromped down on it the miss didn't go away. checked cap looked okay. the plug was spotted white. I just ordered the spider. I also noticed I've been using more fuel lately.

Higher fuel use and the misfire could mean the poppet valve stuck open on that cylinder. The white sounds like fuel deposits. A quick test would be to pull that plug, then start the engine and see if you get a heavy gas smell or mist coming from the plug hole. If you have access to a compression tester you could check that as well. That would show if it was a sticking valve or other mechanical issue, but I sort of doubt that.

I'll compression test tomorrow.thanks

Good morning. I took compression test. number 2 cylinder has 0 psi. the cylinder beside it has 180 psi.

Got valve cover off. the rockers and pushrods seem to be working up and down like they should..

Compression in# 2 cylinder has zero compression. does anybody have one last suggestion? someone mentioned seafoam. would that be worth a try? I never used it or what it does. clean carbon maybe. would carbon build up that much to where a cylinder would have zero compression. I want to thank you all for suggestions.

My opinion is burnt valve. I just don't understand the truck run great then all of a sudden zero compression. thanks

The truck does not smoke at all. Come on all you wrenches!

Zero compression isn't good. About the only thing that would cause that is a valve failure or a piston. If you can get a borescope you could use it to look into the cylinder and see what is going on but first try backing off the rocker arms on cylinder two, if one of the valves broke it should show itself as you back off the rocker arm. They are not adjustable so putting it back together is just tightening them to 22 ft lb. once they seat on the support arm. That should point out if it's a head or lower end problem.

Hello CarPros. I started tearing my truck down. I found a bent push rod on# 2. so l'm taking the head off. I'll keep in touch. thank you guys!

Hello CarPros. I got my right side head off today. I have a bent valve along with my bent push rod on#2 cylinder. I had to lightly tap out valve .I took out the valve from cylinder next to it to see how it fit in the valve sleeve from#2. it feels nice and tight and smooth. it's my belief I could lap another valve in#2 and would be okay. my problem is, I don't understand what caused this. I had no check engine lights on before this until I tromped down on my gas pedal. my only thought is maybe faulty fuel injection that made that cylinder hot and causing the valve to stick and bend it and push rod. I'm asking what would be your thoughts. I did buy and have the new fuel spider. thank you so much!!
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Bent push rod.

That will cause the misfire. Good job finding it. Unfortunately you got hit with the binding valve stem issue. What likely happened was that you stepped down on the gas, the valve opened and had a slight bounce which caused it to bind, the piston came up and pushed it back into place, but now the bent stem was enough that the pushrod bent when it tried to move the valve again. Wouldn't be the first time. What I normally do with them is to pull the head off, remove the guide, install a new one, cut the seat and lap in a new valve. Or because they are sort of a known issue I'll even run a reamer set at the proper size for the guides bore and run it through them, just to be sure they are clear and round. Then do a valve job on the head.

The top of the piston has a little scuff mark where it pushed back the valve but looks okay. I'm buying a remanufactured head and putting it back together..

Sounds like a plan. That is basically what I do in the shop if possible. I would likely pull the other side off and clean and lap that side just to check it and maybe avoid a similar problem there.

I pulled the other side replaced valve seals and gasket..thanks so much.

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