Miss but no check engine light

Looking for suggestions. My 2005 4.0 has a bad miss but no trouble codes or check engine light. It is more noticeable in gear with foot on the brake than at idle. No real noticeable loss of power under acceleration. Since I have a 2006 also, I have been swapping parts but have had no change. Here is what has been swapped or replaced. Plugs, mass airflow sensor and ignition coils. I also removed and cleaned the throttlebody. Plugs all looked worn but not wet or oily. Changed oil, no coolant in the oil. No visible damage to vacuum lines or upper intake. Any ideas?

Thanks!

 

Fuel delivery system. You've checked engine air filter?

 

Forgot to list it in the items I changed but, it has a new air filter. Anyone know how to test an injector?

 

How long has this been going on? Fueled up from any questionable sources lately? I'd start with checking your fuel pressure at the rails.

 

Its probably a bad injector. But Maticuno has a good point. This will help if it's the injector. Links below

http://www.customtacos.com/tech.old.../06toyrm/06toypdf/06rmsrc/rm2006ta/009001.pdf

If you have a bi directional scanner you can turn off injectors one at a time figuring out what one is causing the problem. If you don't have the option try unplugging one at a time until it doesn't sound much different than it does before you unplug it and it may lead you to the problem injector. Then just change it out.

Good luck.

 

Almost embarrassed for the cause of the miss. Turns out that changing the plugs fixed the original miss. However , I cracked the plug in cyclynder number one causing a new miss. Thanks for the suggestion.

 

Well at least you found it. Better than taking it to the shop. An added bonus was a valuable lesson on removing / installing spark plugs.