dakotar95

hey everyone, so im trying desperately to find this miss. I have a code 25. The exhaust sucks air ONLY when i hear a miss from the tailpipe, intermittently, maybe once a second, or one right after the other. Tried pulling each plug wire one at a time and every time made the truck run worse. Maybe burnt valve, BUT all cylinders had between 170 and 180 psi. I checked twice. Also every spark plug looked the same which was white. When the engine is cold it doesnt miss at all, only when warmed up. How does a valve go bad only when the truck reaches operating temp? If a valve was sticking when it got hot wouldnt it miss on that cylinder every time it was supposed to fire? Not once per second? I dont doubt i have more than one problem going on at once. Another issue, related or not, is it misses really bad at around 1800rpm. past that its fine, WOT its fine. I tested the tps and it was in spec and didnt find any dead spots. Someone was also into my afm. i marked it where it was when i got it and found that it ran a little better richened up a bit. Also changed the timing belt to make sure it wasnt off a tooth. Im at a loss. Sorry for the long post but just wanted to let you guys know everything ive tried.

please help lol

toiyodah4WD

Something to think about is either cleaning or replacing your injectors. I had a miss of some kind and consistent off and on code 25, now no miss and no 25, but a code 26 after grey top Flamethrower injectors. My mpg is 15 more or less consistently so I'm happy enough with that. The ecu may figure out the new injectors yet, I'm at 1K with them. And I console myself knowing engines running rich are cooler than engines running lean. Injector cleaners don't work enough to make any difference (as you probably know). I also posted an EGR valve cleaning suggestion which helped a loping idle. Truck has good torque, power, acceleration, no hesitation or stumbling and decent gas mileage with this formula: timing at 13 btdc; ngk iridium plugs gapped .036, 93 octane, flamethrower injectors, EGR valve cleaned out. Bottom line I think a lot of 3VZE code 25 problems can be traced to the injectors being compromised. Maybe I'd recommend as close to stock as possible.

dakotar95

ya i could probably use some new ones, or to get them professionally cleaned. im suspecting somethings wrong with the egr valve/ system. creating essentially a vacuum leak through it by sucking too much exhaust. and that might explain the sucking from the tailpipe. thats whats got me hung up the most right now. i might take the egr valve off and plug the connections to see what happens

dakotar95

ok so update. The previous owner had changed the AFM a few clicks, i assume to richen up this lean condition, but didnt mark where the wheel was stock. after trying and trying to get it right i gave up and bought a new one which helped a lot and improved mileage from 12mpg to 14mpg...yaaay. but still had a lean code and a miss. I also replaced the egr. That helped a TON. more power throughout the rpm range, especially wide open throttle. so far no lean code but still misses at idle. its like my truck had a bunch of problems all at once.

If i retard the timing at idle the miss stops. but then doesnt have enough timing while driving, just kinda slugish. my timing is way off the timing tab when checking with a light. it doesnt change when i jumper te1 and e1 so its impossible to check timing. ive heard if the throttle position sensor is out of adjustment it can cause this timing issue? theres a couple threads here talking about it but no real solution

millball

Yes, a bunch of problems at once when folks tamper with things that they don't understand clearly: then a cascade of troubles ensue.

You say that there no real solution to possible TPS issues??

How 'bout determining that the TPS is sound, and adjusted to FSM specs????

What is your idle speed. Too high idle speed will foil base timing adjustment too.

dakotar95

well i had already tried adjusting it once and it was all in spec and no dead spots that i could find. but i did do it alone when i could have used a second set of hands. i couldnt find a way to keep my multimeter leads on the contacts without touching each other or other posts. i managed to hold them with one hand and put the feeler gauges in with the other.

that was going to be my next step, grab another person so i can do it more accurately.

right now it idles at around 900rpm. very consistently

millball

The issues with dead spots and such in a TPS are usually due to wear, or dirt in the unit and mostly have to do with performance problems under load.

Ordinarily, replacement of the TPS is the fix for that .

What you are looking for is that the TPS sends the proper signal that the throttle is closed at idle.

dakotar95

ya i guess that could be. like the computer doesnt think its actually idling so its trying to advance the timing too much?

millball

Exactly

dakotar95

Awesome thank you! ok i will try to get to that today and re adjust it and see where the timing is after

millball

Try using the idle air screw and dropping the hot idle another 50-75 RPM too.

Good luck!!

dakotar95

Ok so I re adjusted the tps with a helper. 100% sure it's correct this time. Put everything together and lowered the idle to 850. Put the jumper in and the idle didn't change. And the timing is so far off the tab idk what it's at. The mark is almost directly on top of the balancer pulley. I can lower the timing to where the mark is down to 15° to get an accurate reading but putting the jumper in doesn't change it. It stays spot on at 15 with or without it. Check engine light is flashing so it's in right.

Anybody know where the timing is supposed to be at idle on these Toyotas WITHOUT the jumper in? Seems I could set it that way