Engine car acting up

car acting up

lately when i have been driving its been "jerking" at random times like it is missing or something i have no idea what it is anyone have any suggestions?
its a 98 jdm 1zzfe and no a/c prolly 55k on the motor and ive 2000 miles since my last oil change the only thing i did different is i changed to synthetic last change i used the Royal Purple

help me out peps

timing could be off, filter could be clogged, injector(s) could be clogged, plugs could be fouled.

im hoping its just the plugs how hard would it be for the timing to be off on a chian system?

Not sure if this is going to help any...

Back about 3 years ago, the ECU...SUDDENLY failed in my '96 firebird. You could get the thing above 2k on the tach...but it would jerk around like it was about to fall apart.

Dealership never did say anything specific, only that part of the ECU fried.

When does the jerking exactly happen? Cause my 98 used to jerk when I pressed on the gas slightly more than half way and it ended up being my coil packs

it does it at random times i can be crusing a 60 and it will do it everyonce of a while i can take off slow or fast and it sometimes does it then too

Could be something wrong with the delivery of fuel and fire.

Starting with fire (ignition components
Check the simple stuff - pull the plugs out and read them - see if they are fouled in any way. If they are - just get some new ones. Check that the inginition system is in good shape - the coil packs (igniters) are good, wires in good shape. Might try running the engine somewhere very dark with the hood up, varying engine speed - might be able to see if any spark energy is shorting to ground before it gets to the ground electrode of the plug. Loose or intermittent ground connections cause all kinds of electrical issues - do you notice if the headlights dim when you run any extra accessories? Check the condition of the battery and alternator - they they are weak, also causes some electrical issues to pop up.

Fuel (fuel components, injectors, air induction
Make sure that you are getting fuel to the rail. Make sure there is no holes in the gas lines, EVAP hacks, leaky vacuum hoses. Check health of fuel pump - fuel filters are clean (filter sock and fuel filter are in the tank - remove access panel from under rear seat to get to it). Make sure your air filter is clean - might not hurt to give the throttle body a cleaning, getting all varnish carbon buildup. Run a bottle of strong injector cleaner though it - Redline make some strong stuff or switch gas stations and see what happens (could be a bad tank of gas).

If the engine is stumbling on you - should have thrown up a CEL for misfire or similar. Even if you don't see any CEL - see if Autozone or similar automotive parts outlet will scan your OBD-II ECM for stored codes - might go a long way in diagnosing the car. Otherwise, you'll just have to start throwing money at it and hope that you replace the defective component.