DupermanDave

I just replaced the water temp sensor in hopes it would help my idling issue. Lately, when I'm driving down the highway and I come to a stop the truck idles at 400-500 rpms, and surges up and down like the computer is trying to compensate fuel input and keep it from stalling.

If it sits for about a minute or a minute and a half, it will go away and idle normally at 800 rpms. ocassionally, if I mash the gas pedal it will help make it go away as well.

What else should I be looking for? It seems to be getting worse. Last week it would idle at 600-700 rpms at lights, not it's down to 400-500. What else should I look for?

I should also point out it's fine when it first starts up. It's only when it's warm does it do this.

yoterr

in park (or neutral) with the engine running smash ur brake peddle, if your idle changes then u have a bad booster, had that prob with a bronco, allmost stalled everytime you stoped but it idled fine..just a possibility to check out

DupermanDave

The brake doesnt affect it at all. I parked it today and left it in neutral on a flat surface and it still sputtered out. It never stalls, but I fear it's getting to that point.

I've checked all the hoses and everything is tight. No vacuum leaks. It has to be a sensor going bad or something getting clogged.

yodercrawler55

injectors are probably getting clogged

DupermanDave

Eeew. I was going to send them into witchhunter during the summer, but I can't do anything about it now. Is there any way to test if the injectors are clogged? I've disconnected the cold start injector and im going to see if that changes anything.

yodercrawler55

not really, the only way to see is to pull them out and check em out. I know on my buddies rig he took it to the dealership and they boosted them to check and see if they were clogged.

SoCalR6

TPS? Sounds like what mine was doin.

yodercrawler55

that what i thought about mine so i did all that and it wasn't it lol

904_runner

TPS?

DupermanDave

Nah, not TPS. this is different than the "idle surge". Mine was doing the idle surge for a while until I adjusted the TPS. Now that the TPS is in order,, the surging has gone away. With the TPS surge, the RPMS would rise from 800rpms to about 1200 RPMs, and keep going. This is different, as the RPMs are dropping, not rising.

I rebuilt the head on the truck about 4,000 miles ago, and I took the injectors out then and cleaned them myself (pressurized each injector and used concentrated injector cleaner through them). Could it still be the injectors? 4,000...and I use lucas fuel additive every other fill up. I usually add techron injector cleaner every month, just to be safe.

thook

I'd check the airflow meter. Search "AFM testing" using thook as the "thread started by" option.

DupermanDave

I looked into that, and what I ended up doing was enrich the mixture (i was fiddling with the AFM a few months ago, and I leaned out the mixture a bit) It seems to be running better. Hasn't sputtered out. But It's only been one test drive so far. I'll see how it goes.

Aside from adjusting the VAFM, I also unplugged the cold start injector. So I dont know which of the two adjustments is the actual fix (if any)

thook

You looked into it? Meaning you tested it, or just adjusted it?

DupermanDave

Read it and began to test it and figured, "what the hey, why not just enrich the mixutre and see how that works for now?" Seeing as how I had to leave for lunch in a few minutes, I knew I couldnt test it all, so I decided to take the spare time I did have and turn the dial counter clockwise and see if the drive to lunch would yield any changes.

I should still go out and test it, but it's getting colder out.

thook

Personally, I'm not an advocate of adjusting the AFM unless you're running some performance mods and/or advanced timing. There's just no need and will affect performance negatively even if only minor.

Nevertheless, test the bugger, eh. Pull it off and take it inside where it's warm. If you have the flapper track going bad, no amount of adjusting will alleviate the problem. The ECU simply can't tell what's going on accurately air volume-wise.

motorhead2u

you should check your fuel filter if you already havent my old 4-banger ran the same I tried everything just turned out that the fuel filter was cloged

DupermanDave

Fuel filter is semi new. Only has 4000 miles on it with the valve job.

DupermanDave

After adjusting the VAFM it idles higher, no more almost stalling, but it still keeps fluctuating. Idles at about 900 rpm, and drops to about 850, then goes to 900 and goes back and fourth for about 10 seconds. It sounds really bad. What else should I check out?

Tried testing the VAFM, but my multimeter isnt working properly. I need a new one.

thook

Um.....how do I explain this again. It doesn't matter if you adjust the mix on the AFM. Yeah, it may idle higher, but if there's a dead spot on the track the ECU is not going to get the correct voltage info. It's going to go up and down as you describe. Trust me on this. Not saying it is your AFM. Just saying it could be. I've been there.

Get a new meter or, if you have a buddy with a 22re, swap out for testing. Or, what I've done is go to Auto Zone, buy one, tell them you're not sure it's the problem but want to have it on hand, slap it on, if it's not the problem take it back (making sure, of course, before you buy it they will take it back.......just don't tell them you installed it!). If it is the problem, you have a reman'd Denso unit that works well with a lifetime warranty.

sas'd22re

ive been having stalling , idling and hesitation issues with my 22re as well. i adjusted my tps, swapped coolant temp sensor, IAC valve, and they all helped in different areas but didnt solve my problems. i unhooked my o2 sensor and the stalling/bogging at idle is gone, so im throwing a new o2 sensor in. try it and see if that helps