86 4runner 22RE
Major hestitation starts around 3500 RPM and car will not rev above 4000. Car idles fine. Replaced injectors, fuel filter and cut off the cat which was running red hot. Still hesitates. Timing is way off as the revs increase so 2 questions.........what is the equivalent of vacuum advance on EFI and how is it regulated. I am leaning towards the ECU or ignitor but could sure use some direction from a more experienced 22RE wrencher. Thanks in advance

 

There was another person on here a few weeks ago that was having problems with the timming not advancing at higher rpm, his problem turned out to be a bad ignitor, as for the timming, have you ever had the timming chain and guides replaced ?.

 

Have you checked everything else? Good plugs, wires, cap, rotor? Is there no signs of tracking, arcing, or wear, then..

Ignitor or possible high idle short from the ignition system..rotor, cap, wires, plug. Park in the garage, have someone sit in the driver's seat and while in neutral, bring the idle up to 2500 while you watch for tell-tale blue sparks coming off the wires. Turn the engine and ignition off.

Pull your plug connectors and look/recheck for tracking and do the same if you haven't checked the rotor and cap lately.

If you want to isolate the possible short, or bad gapped plug, while the engine is at low idle, and using insulated plug pliars, carefully pry a plug to dist connector and take a test lead and insert it into the cap while running it to the ground point. If there's a short, your idle won't change. If the wire and plug are good, your idle will drop slightly.

You want to do this before buying or borrowing an ignitor, because if it has possibly blown it's either just from age, or a short fry'd the circuit. I've seen people spend over $200 on a factory replacement ignitor to just short it out again.

 

Just talked to someone with a simular problem. Turned out to be the wrong spark plugs with a too big gap. Check that. You never know.