Need help
Check engine light is on and blinks upon acceleration. I have a friend who is a mechanic and took it to his house checked it with a code reader. Reader came back with P0302 trouble code random misfire #2 cyclinder. We swapped coil packs, install new plugs, new wires, check fuel injectors with stethoscope all were clicking. We then went to the Chilton manual and for that code there can be coolant sensor, mass air flow sensor,fuel system pressure problems. Checked all sensors and replaced fuel filter. I did find the radiator cap broken and replaced that along with a new gas cap. All of this and I still have the same misfire. Has anybody heard of this problem??

 

Don''t be intimdated about posting this up in the 3rd gen section also to get better response.

You swapped coil packs so is it safe to say that #2 cylinder is still the misfiring one?

How does one check most of those sensors? You mean resistance was measured and it meets factory specs or what ?

I am no mechanic but will gladly help you talk this out.. you seem to have some mechanical knowledge probably much more than I do.

You did clear out the code right? Tell us what you did for that.

(not sure that would still be causing the misfire however)

Also be aware of Ultimate Yota, T4R.org, IH8MUD, pirate 4x4 for more response also.

 

Hi Ron, thanks for your reply. I'm not sure how to bump this to another level.

 

INLAND EMPIRE FTW !!!

Temecula right here <----


Sorry I cant offer any advice on the problem, But welcome to YotaTech..

 

-What type of plugs are you using?
-What type of air filter are you using?

 

Did you clear the code? You can just disconnect the negative terminal from the battery for a few minutes to restart the ecu. And a moderator will move the thread if he sees fit.

 

Yes I cleared the code each time we did something then drove it. The light would either come back on right away or after mile or two.

 

Thanks it's good to be here

 

I'm using recommeded plugs and a standard air filter

 

OK, so then you are using Denso or NGK double grounded plugs, and a paper filter.
So it should not be the plug, nor is it oil fouling the MAF.
Id give the MAF a clean for s and giggles.
Since you are not getting 2 misfires, and the misfire does not follow the coil, then your coil is most likely ok.
And you said you changed your wires, so they should also be fine.

 

thanks guys for giving some input. Hope the bump got it some attention

I am presuming the code has stayed consistent-so it is telling us it is the #2 cylinder
so has to be the plug or the plug pack right guys? or not that simple...?

 

I checked the MAF also I forgot to include that.

 

Since its an even code, the issue may be plug, wire, coil. But if the code doesnt move around then it should be plug or wire.
When you switched the coil packs did you clear the codes before reading again?
And these are denso or ngk double grounded plugs right?

 

Yes double grounded plugs, they might have 500 miles on them. And yes I cleared the code each time I swapped a coil pack.

 

Next time, once you clear the code with the OBD also discon. the negative battery. Apparently from what i have read re: misfires is that clearing the code via OBD wont change the baseline set by the ECM, but discon. the -ve terminal will.

 

then try moving the coil pack

 

I will give that a try and let you know. I don't have the truck with me I ride a motorcycle to work. So I will reply tomorrow. Thanks for all your help!

 

It just seems odd, as it seems like the coil is the culprit.
Other things may be the o2 sensor and cat., but I;d trouble shoot the plug and coil first.