Troubles after Tune-up; Why

A Couple of months ago, I gave my 04 Tundra a tune-up inwhich I changed the spark plugs. Ever since, I been having anywhere between 6 to 7 codes ( some repeat till total of ten) ranging from p0171, p0172, p0442, p0113, etc. I also had changed O2 sensors a couple months prior to that.

Last moth, cylinder 6 misfire, placed new coils and sparks. Now 6 codes and cylinder 8 misfire.

I don't understand what's the issue and why?

 

Toyota plugs or aftermarket? Are they gapped correctly? (OEMs should be by default)

Did the codes start before or after the 02 sensor change?

 

I bought them at O'Reilly's. I also have codes for Mass Air Flow and small leak too!

 

Buy some CRC mass air flow cleaner and check the gap on the plugs. By default, unless you gapped them, they’re probably wrong. Then go from there.

I don’t know the history on aftermarket O2 sensors but everyone here recommends Denso which is the OE equivalent to avoid issues with those. Cheapest place to buy authentic ones is on Rockauto. Stay away from Amazon.

 

Which specific brand and model of spark plug did you use? This is important info.

Please know, as is referenced in the TSB section here, the EVAP leak (p0442) is a known issue for trucks '03-'04, the OEM fuel filler neck cracks creating a 'small leak' EVAP code. More info. Although having an aftermarket gas cap or failed gas cap can cause P0442 also.

But I suspect you have two things going on here, not just one. If a lot of this started after tune-up, and that's the ONLY work you've done, changing the plugs, then we should explore WHAT plugs you used, since we know you got them at a reputable place.

 

Were your coilpacks cracked? I think it causes weak spark and is triggered by humidity.

 

Wrap em in a couple layers of e-tape? Foil tape? Whats the best way to bandaid a cracked or 'leaky' coil? Someone call project farm.

 

I’d also like to know, as all 8 original coils in mine still worked but were beyond cracked up. I replaced with the only two densos in stock for 100mi (besides what advanced auto supposedly had in a warehouse). All but two of the boots are good enough to reuse though. My others are Delphi, ngk and one of oreilys “import direct” (had to have the valve covers done that day and didn’t expect to do coils) with no real issues. Eventually putting some junkyard densos in so the block looks more normal for my inspection station…

My non OEM exhaust sensor has only lasted a year before throwing the same code as before.

Also went for the Bosch iridium’s as they were pre gapped, from a good reputable industry leader, and 9 bucks a pop. No issues there.

 

Any and all info is helpful. What was MAF code, for ex of the 4 valid codes for MAF, P0102 .would mean it's possibly not plugged in good. Actual number definetly helps. Also, what are you meaning by "small leak" ?

 

Thanks everyone for your suggestions. I finally found out it was a leak on the line from pcv to body throttle which was covered. Did sprayed an entire bottle of soap water trying to find it,

 

Thanks for the follow-up. Always appreciate when folks come back and fill in the blanks!