Help diagnosing intermittent engine stall...

So for the past 6-8 months, Every once in a while sitting in stop and go traffic, when I start to apply the throttle, the engine stumbles like it wants to die for a second then it's fine. Maybe 4 times it has actually died most of the time it just stumbles. It's fine when I'm coming to a stop, and it idles fine, but as soon as I apply the throttle it acts like its about to stall. It ONLY happens in bumper to bumper traffic, and even then not every time. It does however happen in every gear range (auto trans). Theres no engine codes or trans codes. I thought maybe the TPS was glitching or had a dead spot so I looked at it with an oscilloscope and it sweeps just fine, no glitches. Has anyone had this happen or heard of a similar issue? It's tough to diagnose because it is so intermittent... Any help or insight would be appreciated!

 

Oh yea and its an '01 with the 3.4L. 93K on the clock.

 

Are you on the original spark plug wires? All your ground wires tight?

 

Check for white corrosion around battery terminals.

3
0
2

 

Throttle body / mass air flow and idle air control are some easy things to clean to assist in making things easier to diagnose . I believe there are write ups with pics in here to help .
This along with what others mentioned above would be a good way to narrow the problem down .

 

Yea original plugs and wires, and battery terminals are clean and tight.

 

I also recently cleaned the MAF and throttle body, still had this problem... Haven't looked at the IAC tho

 

Plugs and wires will help a lot .
Nice yota !!!

 

Thanks man... I'll probably swap out my plugs and wires soon

 

This!
It wouldn't hurt to try. Plus, if they are original, they are due for a change.

 

Gonna go ahead and bump this up as im still having this issue and it is becoming more frequent. All of the following has been done since I've been having the issue and none have helped at all:
Plugs and wires
Fuel filter
Couple of oil/filter changes
Cleaned MAF and throttle body

I'm beginning to think this is a transmission/ torque converter problem. It's been 37k since my last trans service, tho this started about 15k miles ago (truck has 97k on it right now). It threw a P0770 code a few weeks ago which is a torque converter lockup clutch solenoid code. Ever since it tripped the code the problem has become worse, but it hasn't tripped a code again. I plan to do a full trans flush and filter replacement in the near future to see if that's helps...

Any additional input is appreciated.

 

Sounds like you might have found the problem then,,or one that is set to fail soon.

It might have popped a code when it was really struggling,,and then not again because it is not struggling enough to throw it again,,but still on it's way to failure.

Something like that would definitely cause the same type of situation.

If it continues after your filter and fluid change,,then investigate your code a little closer. It reads like you have covered most of the easy things.

Slush boxes(Auto's) are a finicky animal sometimes.

 

Yea they really can be a pain in the ass sometimes. I'm hoping the flush will work... I'll post updates if I make any progress on the problem.

 

Here is a Little diagnostic info that might help
http://www.tacomaworld.com/forum/te...warner-340-series-transmissions-write-up.html

 

Yep you and I have already talked in that one. Thanks tho!

 

I had the same stalling problem when I first got my truck, but in my case, TPS is all it really was. The problem went away after I swapped it.

 

Was your stalling constant or intermittent? I tested the TPS when this problem first started happening as that was my first thought, but it was good.

 

Update: I did my trans service and filter change today. My drain plug was cross threaded by whoever at Toyota did the trans service at 60k, and since I was dropping the trans pan anyway I just popped a corner of it and let it drain before fully removing it. It sucks that I can't do a regular drain and fill, but I didn't want to buy a new pan... Anyway, I've driven the truck maybe 15 miles with the new fluid and filter, with multiple stop/starts, and I haven't had a single stumble or stall yet(knock on wood). I'll report back after a few more days of driving to let you guys know if I solved the problem!

 

Nice.

fleabay or a junkyard for the donor pan. Easy one,,but does indeed suck. Personally, I would have got the pan then. I hate that silky oil running everywhere because that chit never heads for the pan I have in place when I have to corner dump one.

I got ahead of the game from the get-go,,and just use a pipe wrench.

The trick is to snug that drain plug just a bit, before trying to remove it. Just a couple handfuls of pressure,,before trying to back it out. Your break the crud and sometimes dissimilar metal lock the easy way, then it backs out easy 9 out of 10. Another trick to add to the bag.

Bad tools equal a overtighten every time. That and non-experience.

Wont hurt to run it another motor oil change or two and do another trans change then. Time for gathering parts and stuff.

 

Another update:
After about 150 miles, the stumbling happened a couple times. Nothing nearly to the frequency that it happened before the trans service so it was pretty obvious that the new trans fluid helped a lot. So today I bought three gallons of ATF and did a full flush. I did it by popping an ATF line off the radiator, idled the truck to let it pump itself out and refilled it thru the dipstick tube. It was pumping out faster than it could refill so I had to turn the truck off a few times to top off the fluid. But overall it seemed like an effective way to flush the fluid. So I'm pretty sure I shouldn't have any more issues at this point.