Weird complete loss of power. Help?

98 Tacoma 3.4L manual. 210k miles

Little background on truck: I bought the truck from a military Kid a few months ago. He Had paperwork for a bunch of work, new clutch, less than 40k on timing belt, new MAF sensor a few months ago after I first got it.

ANYWAY…

Tonight while driving home on the free way I get to about 75ish miles and the truck kinda dies for a second. I’m talking .5 seconds maybe. During that split second the check engine turns on quicker than a blink of an eye, but I lose no on electrical power to anything in the truck. Just complete loss of engine power for less than a second. I almost thought someone bumped me from behind lol. I tried recreating the problem multiple times with success. Seems fuel related because when I give it a certain amount of gas no matter what gear it does it. But if I put it in neutral, and match the rpms it was doing it while in gear I get no issue. Today is the coldest day we’ve had here in my city this fall so I’m not ruling out temperature related, but I’m assuming it’s fuel related, here is my reasoning, please lmk if I’m wrong: when giving it gas In neutral there isn’t as much load as there is when giving it gas in gear attempting to move the truck.

Usually I wouldn’t be too concerned because I have a spare truck, but the fiancé is driving it since her car is in the body shop after getting t boned. Usually I’d park it and try to figure it out myself, but obviously I’m not in the situation to do that now.

 

Throttle position sensor?

 

You said check engine light came on.....
You need to pull that code. Most auto parts stores will do it for you if you don't have a code reader.

 

Yep, the code that was set is your starting point for diagnosis

 

The code should help!

Most all fuel related problems unless it is causing a Miss will not trip a code .

Best guess the ECM drops out for a second.

If there is no code your seeing the check engine light because the ignition is in the run position and the engine is not running the engine starts the light goes out.see any of the other normal warning lights ??

Manual transmission a spinning engine compression start

just a guess I am curious what plays out.

 

No codes with my outdated matco scan tool. The scanner has always been unreliable so I checked with my cheap on and still no codes. I checked all grounds I think, and checked fuse box for loose wiring. The ground wire nut out of fuse box (o think was ground I was rushing before work) was not tight, but not loose. I got about 1.5-2 turns out of it with 1/4 ratchet. I know enough about cars to get by, but I’m a diesel mechanic 2nd year in so some gas car stuff I don’t know. Any suggestions on some diagnosticss I should try to trouble shoot short.

 

To clarify the check engine doesn’t stay on, it comes on for a fraction of a second like when you kill a car.

 

What kind of MAF sensor did you install, Denso/OEM or aftermarket?

 

Sorta sounds electrical to me. That flicker of the check engine light is the thing thinking the engine has died completely. I would start with the basics like a loose battery cable and check all the connectors.

 

Is it possible the timing gear key way on the crank got wallowed out causing the gear to move and causing erratic cam timing changes?

 

Cam or crank sensor failing

 

UPDATE: Just got to work, tried to duplicate issue countless times. Giving it more throttle on large hills in 4-5th gear. Also tried going up to 5k in all the gears flooring it, could not replicate issue. It’s colder today, but not as cold as last night, I will attempt to duplicate the issue tonight when it’s colder on way home.

I wanna thank y’all for the quick replies so far, didn’t think I would get many opinions (my first post). Thank you guys!!! Hopefully it was just a weird occasion, likely not, but hopefully. I assume it’ll do it again tonight haha.

 

An electrical gremlin causing the engine to stall then because you have a manual transmission restart.

Does this truck have a tach? does it drop to zero and rebound when this happens?

Since you state no other electric fails this is in the ignition /ECM area.

Good Luck!! Intermittent problems are a pain.

 

at this point if it were me I would start by wiggling wires and harness's, not jerking on them, moving them with an index finger in an attempt to replicate road vibrations. Start at the battery positive post and follow each harness and wiggle it. If nothing in the engine compartment then take the knee panel off and start at the ignition switch harness and do the same. As mentioned above it is something that is more than likely ignition related.

 

I suspect that you may be experiencing a temporary lack of fuel pressure at a certain engine load. I am wondering if an automotive tech would still perform a fuel volume test for your 6 cylinder engine or if they strictly go off of a fuel pressure test. Anyway if you are starting to develop a fuel restriction these would be the components that I would look at although in no particular order. In tank fuel pump, fuel filter, fuel injectors, fuel pressure regulator.

 

Check the connector to the ignitor mounted on the passenger fender.

If it is loose the engine may stall over bumps that jostle the connection

 

I don’t think the tach moved really.

 

UPDATE: Tonight was as cold as last night, and it did it a few times on way home. I payed attention to as many variables as I could tonight.

-Hitting bumps didn’t seem to do anything, sometimes it would do it, but I hit some bigger bumps on purpose and when I did that nothing happened. I’m not ruling out bad wire or connection and plan to try the thorough check while jiggling wires as someone suggested above.

-It happened in both low and high rpm, gear, and speed, but seemed much more common when I give it more fuel at higher mph. Consistent Rpm doesn’t seem to have to much to do with it while cruising. It seems like when I give it what I’d like to call passing throttle (passing slow driver) it likes to sometimes occur 7/10 times. So this again is making me think fuel related.

-To clarify I didn’t lose power to anything, headlights, radio, heater, interior lights, nothing turned off. The tac, Speedo, fuel, and other gauges did not move, all acted as normal. As I said before the check engine illuminates for less than a quarter of a second, gone as fast as it came.

I’m just puzzled, what would cause it to do it in 25 degree weather but not in the 60ish degree I had earlier today? I’ve been brainstorming all day.

I’ve been thinking of better ways to describe it to y’all. Imagine driving 65mph. And someone presses your brake pedal down 25-50% and let’s go all within a second. Almost like I’m brake checking someone.

 

cable driven I believe. Unless you’re making a joke. I’m confused haha.

 

My bad. Drive by wire. In the old days there was a direct link between the gas pedal and throttle. Nowadays its drive by wire. Somewhere 2000-2005 vehicles went drive by wire.