Engine dies after WOT

[Wolfenburg]

This last weekend my truck died on me twice. Both times right after I gave it wide open throttle. The first time I was yielding to traffic so I gave it some gas, just a few seconds later at the stop light I realized I had no power steering, dash aux lights were on ect. The truck started right up and ran just fine. Second time was the same story except the truck took a few seconds of turning the engine over start back up, for a second I was afraid it wasn't going to start..

I cleaned my MAF & throttle body about 2 months ago, K&N stock filter replacement about 5 months ago.

Im thinking fuel pump first, O2 sensor and maybe TPS? Give me some advice if you think there is a better place to start. Ive tried to replicate this problem with no avail. It does it when it wants. :nono:


I have a 99 automatic 3.4 limited twd. I have searched the threads and but could not find these exact symptoms. If someone could give me some good places to start checking other than those that would be awesome. Thanks.

Dont I wish every vehicle was as easy as my bug..

 

[LittleCaesar]

Any codes?

 

[djskorch]

My truck has done this a couple times also. It would only happen to me after a wide open throttle jaunt as well.

Basically, full throttle pull to about 70, let off gas, truck would shut off, bump into neutral, start right up, back into drive and keep going.

Never any codes for me and hasnt done it in a long time (almost like it stopped after putting on the supercharger).

No clue why but odd indeed.

 

[HedgehogOutdoors]

Mine has done this twice, both times while in neutral at under 10 mph. One was going downhill, the other was uphill. Common problem, perhaps?

 

[djtc]

this happened to me today, even after I cleaned the maf and replaced 02 sensors .I have a P0172 code.

 

[Castaway]

Same thing has happened to me in the past. Seemed to get better after I replace the Front O2 sensor (after a while it finally threw a code), but still happened from time to time. No idea why, but if you figure it out I am very interested to know.

 

[PATCO]

I know this thread is old. My runner does the same thing. After WOT such as in the dirt it just dies. It has also done it after passing a car and then slowing down. Afterwards it will start, but won't idle. Throttle is required to keep it running. After shutting it off for a while it is fine. O2 sensors and tuneup were done. Has anyone found a solution? I'm thinking TPS?

 

[wake_rider]

I had an old Ranger that did this same thing, and it ended up being a fuel filter. No joke.

 

[Myrunr2010]

I know this doesn't help at all but....I had a second gen in college that just died on me while going down the backside of a mountain. I was able to keep clutch starting it to keep the brakes and power steering going until I could get pulled over. Once I got pulled over I could get it to start and run but had to keep heavy on the gas, it was putting out a lot of smoke. Finally cleared up and it was fine, never did it again.

 

[JRZEE2000TR4LTD]

Yep, Mine did this also, on the way back from AutoZone where I had just purchased a fuel filter. After getting towed home, the next day I was able to start the truck by giving it gas while trying to start it. Thought it might have been the IAC, but why it did it after WOT didn't equate to an IAC problem. I put the fuel filter in anyway. Hasn't done it since and have tried to get it to do it again. Got on it pretty good on my way to Florida and back. Very strange.

 

[Granada7]

This happened in my first car a jeep (yes i know horrible choice) but it happened to be the computer in fact after a while we found out can eventually crash just like a regular computer once replaced worked great for 6 months before was lost in an accident.

 

[Myrunr2010]

I know this doesn't help at all but....I had a second gen in college that just died on me while going down the backside of a mountain. I was able to keep clutch starting it to keep the brakes and power steering going until I could get pulled over. Once I got pulled over I could get it to start and run but had to keep heavy on the gas, it was putting out a lot of smoke. Finally cleared up and it was fine, never did it again.

I guess I should note that just a few months after this the truck "spontaneously combused" in my driveway

 

[Spunk]

Mine does the same now adays. It's annoying, but workable.

I may replace the fuel filter soon, but the easiest fix was to keep RMPS reasonably high after WOT. let the engine hang around 4000 RPM before letting off the gas completely. This gives it the chance to do something majical, or more often then not, shift gears. After shifting (Automatic), letting off the gas was no problem.

 

[Troybylt]

I will preface this post with the fallowing: I AM NO EXPERT ENGINE DUDE MAN.

My truck has done this to me as well and I can get it to do it if I try every time, I have a manual and when I change gears after WOT nearing red line it will die. When I'm in the high upper RPM range, beyond Max Torque and Max Horse Power (red-line), I spoke to my friend that does engine tuning and in explain like I'm five terms he basically said the engine chokes out, it goes from running really fast with lot's of fuel pouring in to closed throttle not enough air to maintain combustion with the excess fuel and the fuel chokes out the hot engine.

You need to be heavy on the throttle pedal to keep the butterfly valve open enough to allow air to come in, not gas, and burn off the excess fuel hanging around. There really isn't much of a point in going above the max Torque and Horsepower point anyway. I.E. above 4.75k

If it further helps my fuel filter is new as of 10k miles ago and I first noticed this after pulling hard to get beyond a bus and shifting just as the engine reached redline a week after I changed the Fuel filter, so I doubt that it has TOO much to do with the filter. Anyone know if our trucks have a "learning" computer? It could have been runnign higher pressure and longer injector pulse due to the increased resistance that had gone missing after the old filter was replaced and needed to re learn with less pressure and time as fuel was being more readily delivered? Either way that would again point to too much fuel not enough air. It blew my mind when I learned that engines really run off air and gasoline just starts the air burning like a catylist.

I have also trouble shot and realized that If i take it up to that RPM point and allow the truck to slow down without changing gear to around 4k and pull it out of gear it will drop down to idle without an issue. I would imagine an AUTO would drop down to neutral when you come completely off the throttle or shift into it's highest gear and free spin as if it were in neutral allowing the engine to bog and choke.

Lastly someone mentioned that adding a super charger fixed the issue, this further alines with my and my buddies theory as a super charger will be more likely to cause the engine to run lean (less fuel more air) especially at the higher RPM range. It will also shift the max HP/TQ cross point
further up the band and possibly beyond the Red-line of our valve train. Though to be honest I haven't had the pleasure of tuning with a SC 4Runner. (YET!)

In short I believe it's an operator head space error and not an mechanical issue though I am open to opinion.