erock13

I have an 86 4runner with a tps issue.. I havent gotten to fully adjusting yet, I need to buy somethin to dump the coolant out to before i can get to the bottom screw and fully adjust it, but i have it sorta tolerable now, it used to misfire and buck really bad from idle to quarter throttle, but now it will cut out at a slight touch of the throttle while cruising and give a slight misfire, but once i put my foot down a little more it runs fine.. But Ive read alot of posts about ppl disconnecting their tps and it running better, or at least decent.. When I unplug mine, it misfires like crazy, from idle thrughout almost the entire rev range, hot or cold, less so when its cold though.. Could this be an indication of something else thats wrong? Seems like theres something else besides the tps thats having issues..

BMcEL

Adjust and test the TPS first. That way you can rule it out as being a possible cause.

http://www.4crawler.com/4x4/CheapTri...#TPSAdjustment

Then check for codes.

http://www.4crawler.com/4x4/CheapTri...es/index.shtml

Then report back.

BMcEL

Any luck?

erock13

Sorry, havent had much time or money, and forgot to report back.. But yes, I tested the tps, it tested bad, so I bought one from Toyota, its on and adjusted, but it eliminated one misfiring problem, but still leaves another one, its an issue thats been slowly getting worse and worse, which I thought was due to the TPS, but apparently isnt.. For the first 10-15 mins of my 30 mile drive to work, it runs flawlessly, but as it keeps going and the engine gets hotter and I start gettin to the foothills, making it work harder going uphill, it starts misfiring/jerking and keeps getting worse and worse till i basically have to throw my hazards on and limp it at 55mph the last couple miles to work.. It almost feels, sounds, like when I hit the rev limiter on a bike, this kinda gargling sound, like its getting fuel cut off or ignition cut off or something.. So I have no idea about this one, it also doesnt happen on the way home, downhill, usually at night as well when its much, much cooler, it will give intermittent jerks, but nothin that makes it hard to drive.. Im thinkin valves possibly, since it only happens when its hot and I have the engine under a constant load..

BMcEL

Codes?

TNRabbit

Check your fuel pressure. Have you check for ECU codes?

Also, you can remove the hood to adjust the TPS; takes 5 mins & makes it MUCH easier. Also, go to your local Ace hardware or equivalent & get allen head bolts to replace those lame phillips head bolts. MUCH easier to deal with.

Good luck!

john4wd

X2 TNRabbit, Go to ACE and get allen head stainless steel M4-12mm long fine thread 70 pitch machine screws for the TPS sensor on TB for easy adjusting and went to Menards and got there mm package of round ball end allen wrench's for $7.99. ACE and Sears wanted $19.99 and up for same type mm set for angle screwing in of allen head bolts...

erock13

I cleared the codes before I left for work today, and I just pulled em, and got 2, 8, and 10.. AFM, Intake Air Temp Sensor signal, and starter signal. Starter signal is from the push button start thats in, since the key ignition doesnt work.. I guess that means a bad AFM?

Thats actually all already done, read my above post a couple up, those allens are a lifesaver, the original Philips bottom one had fallen out awhile ago so taking the old tps off was a breeze anyway, just as easy puttin the new one on..

BMcEL

Definitely possible...with 2/3 out of three codes pointing to the VAFM or its circuits, I'd start there. FSM testing procedure here:

http://personal.utulsa.edu/~nathan-b...33volumeai.pdf

If it tests good and you still have the same issue, try testing it at the ECU to see if it's the wiring in between.

erock13

Alright, thanks, will test tonight after work.. If it does test bad, would it be better to buy new or find used? And would an autozone or napa be problem parts? Lookin for an 82 supra afm, but not seein anything yet on ebay or craigs..

TNRabbit

I'd stick with Denso. See if you can find a used one first. I don't think NAPA or any of the other parts places stock them....anyone?

BMcEL

x2 on finding a good used one. I'd print the pages I linked to above and take a meter so you can test it before you buy it. And I think a few places do sell 'remanufactured' units but that's not a good choice in my opinion.

erock13

replaced the afm, runs much smoother now, more throttle response, but after it warms up and it starts gettin worked more, same problem.. starts out as a buck here and there and continually escalates till its practically undrivable.. ugh, pain in the butt.. dunno if I should jus take it in and have a thorough diagnosis or continue trying it myself..

BMcEL

Did you test the AFM before you replaced it? Have you checked fuel pressure?

erock13

yupp, first thing i did when i got it, ohmed out perfectly, spot on with the specs.. havent checked fuel pressure yet though.. im thinkin its gotta be fuel or ignition now..

jswizz

damn ! erock 13 . SOUNDS TRYING ? I am having a very similar prob . and am hanging on a thread to see what y'all come up with . I changed my fuel filter and am contemplating the tps and the codes . thanks for all the info .854runner sr5 33x12.5 and level kit

turkey

i had a nissan that did same exact thing and it was maf sensor it would run fine on cool morning but would not get bover 2500 rpms in the afternoon when it was warm. hope this helps

BMcEL

Not only do these trucks have a vane AFM (air flow meter) rather than a MAF (mass air flow) sensor, the OP said he replaced the AFM with one that tested good. Good try though.

turkey

oooh sorry very new to toyota. i have a very unrelated question. what would make my stock 3.0 have high egts?

Yotaguy0001

Sounds like my 92 runner with a 3vze. The exhaust valves were leaking.