I have 95 previa sc having hard time to start and engine lost power

Please check the attached links: http://www.autozone.com/repairguides/Toyota-Previa-1991-1997-Repair-Information/ELECTRONIC-ENGINE-CONTROLS/Throttle-Position-Sensor/_/P-0900c1528008a21b
http://zenseeker.net/Previa/PreviaMaintenance-Engine.htm

1997 Toyota Truck Previa 2WD 2.4L EFI SC DOHC 4cyl

check for worn or broken motor or trans mounts

You need spark to the plugs, fuel to the injectors, and normal compression. One of the three is missing.

1) Adjust the ignition timing according the specification manufacturer.
2) Readjust the GAP for spark plug, with the s. manufacturer.
3) See for loose , break, or burn wires, corrosion, dust, dirty, vibration, solenoid defective, relais, starter, alternator, battery system. Look for diagrams for troubleshooting. GOD Bless you.
You can connect remote start switch, side +to the battery, and the other side to the terminal solenoid, must be RUN,and isolate and fix it according your logic.

CHECK YOUR TIMING BELT

Try this site: http://www.toyotanation.com/forum/forumdisplay.php?f=85
It should have everything you need to know about the Previa. Hope this helps!(RATE IF USEFUL)

95 Toyota Previa van has sparks and gas but doesn't start

Previa ECMs CANNOT be 'reflashed". Whoever told you that the SC is programmed to 'choke' is lying to you; there is no such thing. That is the same with the slip, the engine cannot cause the trans to slip. Get another opinion from a credible mechanic. The one you have has no clue.

95 toyota may have an early obd2 diagnostics,which started for all cars in 96,which means it can track a cylinder misfire,when ck light flashes it can mean multiple misfire detected causing serious loss of power,you can try going to autozone they do free ck engine light code reading ,tell them you may have obd2 plug according to web,let me know codes if you get lucky.with AZ its hit or miss