86 4runner, 22re.. Problem just cropped up out of nowhere several days ago.. While driving on the freeway at a constant rpm it will start to feel like its almost misfiring, and ill lose power.. But on the street, its perfectly fine, not a single issue, can drive ten miles through town and acts perfect, untill i have to go up a big hill, then itll start doing it again.. Starts up and idles perfect as well, Ive had a bad cap and rotor before and it would lurch and buck when it misfired, but it just kinda gargles like its stalling, sounds kinda like its hitting the rev limiter you could say.. Cap, rotor, pickup coil, wires, and spark plugs were all replaced two months ago before my smog test, fuel filter is a year old.. Tps has been adjusted several times and is only two years old.. I will check codes in the morning, but any clues to what this sounds like? It sounds fuel related to me, but im kinda stumped.. Either a bad fuel filter or bad injectors maybe? Ill try getting a new fuel filter in tomorrow as well, cheap maintenance..

 

Fuel pump or fuel filter

 

Sounds like it could be an air flow sensor.

 

fuel filter clogged. also, I would look at the plugs could be fouled

 

Could be you just got a bad tank of gas .Buy most of your gas the same place??

Are you one to run the tank on empty??

Is it warm where you are could be your getting some vapor lock but that is not usually a problem with EFI engines

 

Have you found out what the problem is?

 

Alright, sorry for the delay, been working non stop.. Replaced the fuel filter several days ago with no change, and just today I put in a new fuel pump, which i realized was bound to go out anyway upon taking it out, strainer was torn to nothing, a rubber piece was down in the tank, hose was nice and brittle.. Buuuuuut, no change, still.. Idles a bit smoother and has a harder punch off the line, but once I get it on the freeway, it starts cutting out..

 

I also checked codes, got 2 and 8, both are Afm related but that may be due to me forgetting to plug the AFM back in after I had also went and cleaned out the cap and rotor with some electric cleaner.. I'll clear em and take it for another spin pretty quick here.. Still just an issue under load too, driving on street I rarely have an issue, but once its on the freeway it acts like its hitting the rev limiter, like only two cylinders are firing or something.. Held it steady in neutral at 4k rpm for a good 10-15 secs and not a single stutter.. I do have a spare AFM sitting on my parents shed still I'll have to grab after work tomorrow and see if it could be that..

 

Spark plugs are only 2 mos old, Idk how they could be fouled up already, but its worth a shot I guess..

 

Cleared codes, drove it on the freeway, stumbled awhile, came home, checked codes, no codes..

 

I am curious what your problem turns out to be cause it sounds exactly like a problem I had with an AFM a long time ago. Only difference is I'm running a 7mge.

 

Subscribed.....

 

Swapped in spare AFM I had, reset codes, still no change.. Also forgot to mention I've driven it without the tps connected and without the o2 sensor connected, and no change.. Gonna pull the plugs, see how they look, but otherwise I'll be taking it into a shop tuesday, cuz this makes no sense.. Nearly All my components are OEM or comparable too.. OEM tps, both oem denso afm's, denso fuel pump, wix fuel filter, denso o2, NGK regular plugs, NGK premium wireset, and a duralast cap and rotor, all not more than 3 months old.. So no cheap components here either..

 

I almost wonder if it could be the ignition coil?? Don't they typically have issues under load which is when they go bad? Any thoughts?

 

Im not sure about the 22R's but the 7mge's have an igniter attached to the coil, and I have heard some of my supra friends say it can cause similar problems as your mentioning. Though I would think it would think it would happen anytime the engine is under heavy load, not just on the highway.

 

Tight valves??
When clearances are small, continuious heavy load is enough to heat them until there is no clearance, and then miss and loss of power.

 

Put in a new ignition coil, took it for a spin on the freeway on a portion with a long 2 mile grade, got it up to 82, no hiccups at all.. Final test will be my drive to work in a bit, 12 miles, mostly uphill..

 

Nope, nvm.. Has more.power while its misfiring but otherwise still doing it..

 

Did you swap the igniter when you changed the coil?

 

$524 from auto zone, so no, I def didn't replace that.. :p