Check Engine Light Blinking

[Raymond]

I have a check engine light that blinks when the truck is first started up.
The blinking stops after I drive a couple miles and stays off the rest of the day. Have not been able to find an answer to this problem online, any motorheads out there with an answer?

[Salty]

Try unscrewin' the bulb.

[SULPHITE]

Possible that it means its time for regular scheduled maintenance for your vehicle?? My wife's honda used to do that...she would take it to the dealer and they would turn it off.

[bay_slayer]

It sounds like you are having a problem only during the open loop mode. Which is when the car is cold and the O2 sensors have not warmed up to take control of the air/fuel mixture. But the sensors still do read the hydrocarbons percentage in the exhaust. Now until you get some codes pulled off of your computer I cant help you any further. But be careful because if you are running lean you can burn a piston and if you are running rich you can get a significant amount of carbon build up or burn up the catalytic converters.

You can get the codes checked at autozone for free. IT wont tell you exactly what wrong, but I will get you where to start looking. Let me know what codes you get.

[bay_slayer]

what kind of truck is it anyways?

[Red Devil]

Originally Posted by bay_slayer

It sounds like you are having a problem only during the open loop mode. Which is when the car is cold and the O2 sensors have not warmed up to take control of the air/fuel mixture. But the sensors still do read the hydrocarbons percentage in the exhaust. Now until you get some codes pulled off of your computer I cant help you any further. But be careful because if you are running lean you can burn a piston and if you are running rich you can get a significant amount of carbon build up or burn up the catalytic converters.

You can get the codes checked at autozone for free. IT wont tell you exactly what wrong, but I will get you where to start looking. Let me know what codes you get.

John, you are just the automotive GURU. I officially dub thee, the SaltyCajun auto tech advisor.

[bay_slayer]

LOL.......thanks man........Well I better have some automotive "know how".............I spent 20 something thousand dollars going to UTI and I am Master ASE Certified in all 8 automotive categories. The only thing I dont mess with is body work and I try to stay away from Diesels.


And after all of that I got out of the automotive field after only 7 years. I hated working on others peoples stuff.........I still like to build for myself tho

[Raymond]

2004 Chev Z-71 with 5.3 gas, will try to get it to AutoZone but the light stops blinking before I can get anywhere.

[bay_slayer]

Originally Posted by Raymond

2004 Chev Z-71 with 5.3 gas, will try to get it to AutoZone but the light stops blinking before I can get anywhere.

Thats ok ..............the ECU keeps any codes that pop up in it memory for 200 ignition(?) cycles and if the code doesnt come back it will clear within that cycle. So if it came on this morning they can pull the codes even if the CEL isnt on.

[Raymond]

Code is P 0303 can anyone help a brother out??

[bay_slayer]

Misfire on cylinder 3

[bay_slayer]

that could be a bad injector, spark plug, coil, burnt/bent valve........but should be quite easy to diagnose

[Raymond]

OK, how and who can find out?

[bay_slayer]

do you have any test equipment? First, if your injector still works for that cylinder you need to get this problem solved quick because you can "wash out" the cylinder. The raw gas removes the oil from the cylinder wall and well it simply metal on metal and that aint good. do you have any do it yourself experience? if not you may want to bring it to the shop

[Gerald]

Go out tonight and crank up engine and turn off all lights. Then watch the # 3 spark, wire and look for any sparks.

This is just something to check to see if there could be a "short" somewhere.

Maybe next thing.......would be to pull the #3 spark plug and change it.

Cap on the distributer could be bad.

[bay_slayer]

Originally Posted by Gerald

Go out tonight and crank up engine and turn off all lights. Then watch the # 3 spark, wire and look for any sparks.

This is just something to check to see if there could be a "short" somewhere.

Maybe next thing.......would be to pull the #3 spark plug and change it.

Cap on the distributer could be bad.

You cant do that on his model truck...................he has coil over plugs (no plug wires) also there is no cap and rotor.............all plugs have their own individual coils on top

[Shawn Braquet]

Originally Posted by bay_slayer

You cant do that on his model truck...................he has coil over plugs (no plug wires) also there is no cap and rotor.............all plugs have their own individual coils on top

why couldnt they have just stayed carbureted(sp) and easy? My 90 model jeep could be diagnosed in the mud while stuck and fixed while there.

[bay_slayer]

Originally Posted by Shawn Braquet

why couldnt they have just stayed carbureted(sp) and easy? My 90 model jeep could be diagnosed in the mud while stuck and fixed while there.

So you cant work on it yourself and you have to bring it to the shop!!

[Gerald]

Originally Posted by bay_slayer

You cant do that on his model truck...................he has coil over plugs (no plug wires) also there is no cap and rotor.............all plugs have their own individual coils on top

I figured it might be something like you said.

I guess they don't make them like they use to and engines are no longer simple like they use to be.

[bay_slayer]

Originally Posted by Gerald

I figured it might be something like you said.

I guess they don't make them like they use to and engines are no longer simple like they use to be.

well to clarify myself from earlier...........they do have spark plug wires but not like you are thinking of..........they are only a few inches long and the go directly from the coil to the plug