[7hr Reaperxx]

I have a hesitation and have had this problem several times with varying symptoms. this time I am kinda stumped. The car doesn't turn on its check engine light and runs like it has a bad tank of gas. Idles a lil rough but when you give it trottle it seems to be... a few cylinders short, runs ok at full throttle but pings. (and heads for ditch) lol Have recently changed the oxygen sensors as they were bad (checked with a scan tool). no codes no info from scan tool. what could cause this to happen and not throw a code. mass air is not new but has less than 50k in it same with water pump and optispark, there are no leaks I can see near the opti-spark so I think Its ok. The car itself has 187k on it ussually runs great no knocks and good compression on all cylinders.

[31Vicky]

What about the fuel injectors?

[7hr Reaperxx]

I use the bottles of injector cleaner bout every 4th tank but they have never been out of the car to be cleaned. Discovered yesterday that the car runs perfect till it warms up. then starts the same hesitation and it is apparently going to do that until it has sat overnight. only runs good till it comes up to operating temp. There is a little temp sensor on the water pump, I am going to replace it 1st since its easy to get to. It might need a fuel filter as well its been about 60k since it was replaced. Injectors are for sure a concern though with the milage on this car. Thanks for the help.