One of the first things to do is perform an ECU code readout with a portable scan tool to see if any fault codes are set. The tool can be purchased at most auto parts stores. Post the actual codes here on the forum so that we may be able to help you further. If there is one or more fault codes set, they can help point to the malfunction. If you have a copy of the FSM for your vehicle, the code readout procedure is described there along with a listing of codes. You can download a copy of the FSM from this web site: https://ownersmanuals2.com/
. The section EC.PDF is the one you need to read.
Here are some things you can test:
* - Make sure you have a clean set of spark plugs.
* - Test ignition: Pull several coil packs to test; use a spare plug in the coil pack to test; ground the plug base with a jumper wire to the engine block; see if you're getting a good blue spark while trying to start the engine.
* - Perform a compression test on all cylinders. Standard - 185 psi, minimum - 142 psi.
* - Perform a fuel pressure test. Tee-in a temporary fuel pressure gauge at the output side of the fuel filter. The reading at idle should be around 34 psi.
* - There may be a major intake system vacuum leak: To check the intake system for a vacuum leak, attach a vacuum gauge to a full vacuum source. With the engine fully warmed up, the reading at idle should be 18 - 20 InHg. At 3,000 RPM, it should be 21 InHg. If readings are under 18 InHg, check the intake manifold nuts to make sure they are tight. The gasket may have failed; spray a water mist at the gasket to see if the gauge reading changes. Also check the intake plenum bellows at the throttle valve and at the MAF for cracks or loose clamps.