Fluctuating power and won't start when hot

[JakeD]

Hey guys, for the past few months my 93 v6 4runner will start up no problem when cold but when it's hot and I shut it off, it won't start up again. I've replaced hoses, filters, spark plugs, rotor and cap, and spent countless hours here on the forum searching to no avail, hence the new thread. When it starts cold it has normal power and revs at about 1000 rpm, once warm the rpms drop, I lose power, and it sputters when accelerating harder than a crawl, I've read o2 sensor a lot but before spending another 60 dollars I thought I'd get some expert advice
Any info is greatly appreciated,
JakeD
Btw it's a 93 3.0 with about 165000 miles.

 

[giro]

Is the check engine light on, with some codes?

That rpm is a little low for a cold start....mine is more like 1300-1400. Warmed up it should be something like 800 (check the FSM), so I'm thinking it's set a little low in general.

Once the engine is up to temp it starts using the input from all the sensors to have it decide some things like how much gas it injects into the engine. If it gets bad data in, it will then use that bad data to get a bad result. So if a sensor is bad, if it's only a little bad it can mess things up, whereas if it's really bad it will normally throw a check engine light.

And then there's always the chance that the ECU is bad, or part of the wiring harness. Those tend to be much tougher to track down.

 

[JakeD]

I do have a CEL, and unfortunatley i cant check for codes. the guy who owned the truck before me glued up the diagnostic port.
when i first start my truck it revs up at about 1400 and then comes down to about 1000 when i start driving, then goes down from from there once warm.

 

[77'911]

Check your fuel pressures(rest and running). Sounds like the pump and regulator are giving up.
regards

 

[JakeD]

I'll give it a try! Thanks.

 

[fourwd1]

Don't rule out a clogged cat conv.

 

[CAN-03runner]

I do have a CEL, and unfortunatley i cant check for codes. the guy who owned the truck before me glued up the diagnostic port.
when i first start my truck it revs up at about 1400 and then comes down to about 1000 when i start driving, then goes down from from there once warm.

Easy weekend mod #43 diagnostic port glue up