Backfire, "skipping" but no CEL

Today I was pulling out from work and the truck backfired twice pretty loud. It then started "skipping" when under a load and several other minor backfires while I made it home but NO CEL! Is this normal? (No CEL light that is. lol) Idles rough too. Do I simply start pulling wires until I find the one that makes no difference?

 

Is it a 4 cylinder? I had spark plugs go bad under load but would idle fine.

 

3.4L V-6. Idles rough. Ran fine this morning going to work.

 

I'd start with the plugs pull them and see how they look if they need to be replaced male sure to buy the correct two electrode style to replace them

 

Did you just fill up? Maybe some bad gas? Weird it doesn't throw a code though.

 

Check the fuel filters, can't hurt to go through and clean the throttle body and MAF. Might find something in the process

 

Yeah. I filled up yesterday as a matter of fact with 93. But I was on fumes and drove home yesterday and to work today and like I said, no problems until this afternoon. Weird.

 

Could be coil pack/igniter on its way out. Mine did the same. Ran on 5 cylinders for about a week until #3 misfire CEL came on. Was wondering why I couldn't go as fast up hill. Took a week for the code to come on. That's strange but it happened.

 

Did you replace the entire coil pack or just the boot?

 

pull the coils and look at the boots, if you shop you can get boot kit for reasonable prices.

Odds are one if not all 3 are cooked on the bottom. boots and wires are a good place to start

plugs if you think you may need them ( get the correct dual electrode Densos)

 

Id start with things you can take apart and clean before spending money on parts you might not need. I try taking the Throttle body off, clean that, clean the IAC, the intake manifold and replace the gasket for the throttle body to the intake. Its maybe $3. I used seafoam and throttle body cleaner and it worked like a champ. Drives like its new again. Good luck. Also like many said check your wires, plugs, and coil packs.

 

How often do the packs go bad?

 

my junk has 220k, i've replaced one, but that was only because it was easier to get than the boot kit and i needed the truck, was not really convinced it was bad at the time but didn't have time to thoroughly diag. it was a "Make it run" situation

 

pacs rarely go bad but the boots are basically a short spark plug wire....and they start looking like the one posted above eventually.

 

How about starting with the fact there is no check engine light. When you initially turn the key on, does the light illuminate? If not, you may want to replace that bulb. After that, you should be able to pull codes with a paper clip. Maybe you already confirmed the light comes out...you never mentioned that.

 

Well...this afternoon I was pulling the truck into the garage to work on it tomorrow (been driving the 4R since this started) and FINALLY the CEL came on. I don't have a code reader and it runs way too rough to drive it to Autozone or wherever. How can I check the code with a paperclip as stated above?

 

Here's an explanation of the paper clip method. This is done on an OBDI, I can't confirm if this works with the OBDII




https://m.youtube.com/watch?v=lxks7yRV6Uw

 

Search obd2 paper clip and some you tube videos will come up.

 

I have read numerous "opinions" on the gap of dual electrode spark plugs. Some say they come "pre-gapped" and throw them in while just as many others say to check the gap first. (From the NGK website: "A spark plug part number might fit hundreds of different engines from many different manufacturers. Although the NGK factory will set the gap to a preselected setting, this may not be the right gap for your particular engine.") If the gap calls for .044" is that for EACH side or the cumulative of BOTH sides? ( I read on a post that someone checked the gap and it showed .022" on each side but it called for .044" so he adjusted both sides to .044". I need to know...definitively...do I or do I NOT gap dual electrode plugs? If so, do I gap each side to spec OR each side to "half" spec?

P.S. Code read P0302 - Misfire on #2 cylinder

 

could be some bad gas...maybe try putting some seafoam or something like that. If its not throwing a code yet it might not be quite bad enough for the part to go but will be soon. If the CEL light comes on and is flashing dont drive it untill you fix the problem.