Engine pauses randomly while driving

[Silver dude]

Been have a issue with my engine lately. While driving I note that the engine occasionally rarely without predictability just stops turning for a fraction of a millisecond. Just enough for me to go did that just happen? Doesn't feel like its dropping cylinders. But, like it stops, usually I notice it most in 4wd around 3000rpm as when the engine drops it quickly takes the slack in the driveline and rocks me forward in the seat. Its not coughing or making strange noises. No noise at all in fact. It otherwise operates just fine adequate power ect. Idle occasionally very rarely at times like rarely never happens but yet does skips a beat now and then. I've rebuilt the distributor months ago with a new bearing with no issues after the rebuild. I recently reopened it up and noted it was still tight and in good condition. Cleaned the mass airflow sensor no change. I've got fairly fresh plugs 60k old and wires. I'm thinking I'll get a new cap and rotor this weekend and see it it changes open to suggestions. No codes or check engine light. I'm noticing it is happening more frequently so I'm hoping to knock this out before the inevitable stranded situation happens.

Thinking since it seems to be cutting off its related to ignition as if it was fuel it would sputter and feel weak rather then just... off and back not skipping a beat. Still haven't changed the fuel pump I'm at 176,000 miles. Think it could be the distributor but then I think it would be skipping cylinders or misfiring not losing all cylinders in a instant. Which is why I was thinking maybe the center contact on the rotor as it appeared worn. But, I cleaned it with sand paper and no change. If a coil goes bad well its bad and won't start.

 

[metzican]

Is it like an engine knock?

 

[Silver dude]

Apparently its my front diff. In 2wd with the hubs unlocked it never occurs. Must have a munched bearing causing the drivetrain to bind. Hoping the gear set is ok still. I'll wait till it warms up before I dig into it.

Ben

 

[granitex]

I think that you are on the right track.

 

[xterror04]

i had something similar, but more severe when i sheared teeth off my front ring gear, I got lucky though and got a enitre new front diff off ebay for $20 shipped

 

[Silver dude]

Geez sounds like a bargain. I've found one on there for $189 thinking about it. I think the fault of this stems from me installing a arb locker. This is the 2nd time its munched a carrier bearing. If thats the problem. Must not have the shim packs right. Though I can't really identify why as it seemed correctly installed. Ah I guess have to order a shim set and have another go. If the gear set is good. Otherwise start over. Really feel like wheeling this spring. Luckily long ago I learned if you tie up the driveshafts you can still drive to work. Just gotta wait for it to warm up a little don't want to slide into a snow filled ditch and look like a stuck moron if I can help it.

Ben

 

[xterror04]

Oops mine was $250 shipped, lol I wish it was $20 lol

 

[Silver dude]

Well now its also doing it in 4x2. Crap. It happens so rarely I still can't tell if its a drivetrain or engine issue. Only notice it while cruising. With a 5 speed the engine is directly connected which makes deciding the cause difficult. Coming up on a 10,000 mile service. Guess I'll be inspecting the fluids carefully. Sucks because I feel as though I can't trust the truck. The front axle bearings are bad but that appears to be a separate issue.

Ben

 

[Prime]

I know the exact feeling that you're taking about. That momentary loss and almost instantaneous return of power. I've experienced it both in my Mustang and my old Heep (both manuals). In both cases it was electrical gremlins at fault. The mustang was loosing connection from the factory wiring harness to the ignition coil. My fault because the wires were a little stretched from hiding them out of the engine bay and in the fender well. On the Heep it was a whole different story. Something was causing signal problems with my crank sensor. It would blip out and that would cause the distributor to not fire for half a rotation and then it would pick back up. It got so bad that eventually the crank sensors started blowing out causing a complete engine electrical failure. I replaced the sensor (PITA) 3 times at $60 in about two months. Then I sold that damn thing.

Don't know if that helps at all, but at least I can sympathize. Hen

 

[Silver dude]

Well the front wheel bearing is shot on the drivers side. Its clear that I'm just not having luck with bearings lately. I have my doubts that it's the issue. Yet it eases my mind that the bearing noise is in a area of the truck that is easy to replace. I've had issues with the tiny screws shearing off the lock ring. Sure that's the root cause of the bearing failure.

Ben

 

[Silver dude]

Man its still doing it. Didn't seem to do it all summer. I guess in the winter with the 4wd I notice it far more do to less driveline play. Gotta be a electrical fault. Maybe I gotta beef up the engine grounds. With mention of the crank sensor maybe its time for a new distributor.

 

[Kirk_R]

Mine was doing something similar, it turned out to be the Distributor. Good luck

 

[Rammer'sX]

I read somewhere that it could be a dirty MAF. I talked to my mechanic and he told me that perhaps an intake MAF and throttle body clean may be in order or that perhaps the MAF or temperature sensor may be the culprit.

I am cleaning the intake next weekend. Will post the outcome.

I should say that the times it has happened it is only under certain conditions, temperature is between 20 and 35, it is snowing with snow in the ground and the humidity level is high and the engine's temperature gauge has not reached the normal working temperature



Ramiro Munoz

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[Silver dude]

I should say that the times it has happened it is only under certain conditions, temperature is between 20 and 35, it is snowing with snow in the ground and the humidity level is high and the engine's temperature gauge has not reached the normal working temperature

Exactly! hit the nail on the head with that one. Mine can reach the normal temp though and still kick.

I cleaned my MAF a few months back it didn't make any changes for me. Rereading thru this thread I've repaired everything i've mentioned earlier in the thread. Including a new cap and rotor with full inspection of the distributor.

Couple thoughts keep me wondering.
* When I installed the headers I got rid of the ground strap to the chassis maybe it's creating a signal interference among sensors.
* Maybe a the ground wire for the cam sensor worked itself loose when I installed the plenum spacer (cam sensor ground is on top of intake).
* Maybe with all the mods intake, plenum spacer. headers, check engine eliminators, the fuel map isn't what it should be and brain farts now and then.
* Lower bushing on the distributor is worn creates a light whipping action that now and then throws the cam sensor for a loop despite the new upper bearing.
* Crank sensor got ripped off when I dropped the trans. i put the two wires back in the right order.... I think when I replaced the sensor. No codes.

Hmm temp sensor that's a good one i know the heater gauge on my dash doesn't work and floats everywhere. However, my scan gauge gives a nice digital reading. But, would make sense to fix that regardless. There is two temp sensors and it would link to the weather causing the engine to run poorly.

 

[Silver dude]

Well two temp sensors, one the ECU uses, the other is merely a dash gauge that is it. I can clearly see the ECU one is giving proper readings thru my scan gauge. So that's good. I've decided I'm going to replace the fuel pump, strainer and filter next weekend. At 187k mine is likely on it's way out any how. Problem feels electrical though, if it was the fuel pump it would drop and surge on power I would think. Where as the performance stays constant in my particular issue. I'll dig into the distributor and grounds tomorrow.

 

[Cameron23]

With all these air mods you did it's reasonable to believe that your engine has much more air at its disposal. I'm not sure on out trucks but when my friend did a lot if mods with spacers and intake to his 350z he took it to a free dyno day then had it tuned with to handle the air coming in and he had slight but noticeable hp gains, so maybe your fuel pump was being overworked because it had to keep up with the increased amount of air flow coming in.... Spitballing but couldn't have helped the pump


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[Rammer'sX]

That is what I am thinking too, I may go back to own air box and look into a Osiris tune to better address the mods. Don't know what to do. I will let you know if the cleaning helped this coming weekend


Ramiro Munoz

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[Cameron23]

I'm by no means saying go back to stock! I'm saying have someone check out how your factory tune is dealing with the extra air if it can't deal then custom tune it


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[Silver dude]

Well found the problem... Cone Air filter fell off the intake tube. So when it would snow the engine would inhale the snow and drag it across the MAF sensor causing the engine to jump.

Now just to find a higher quality filter that bites onto the tube.

 

[Muadeeb]

Well found the problem... Cone Air filter fell off the intake tube. So when it would snow the engine would inhale the snow and drag it across the MAF sensor causing the engine to jump.

Now just to find a higher quality filter that bites onto the tube.

Sounds like it's time for a snorkel and an Apollo. :bmmd:

 

[Rammer'sX]

I got the SES light last week and the code was P0170. Decided to go back to Stock and I am ditching the modified air box. MAF, throttle body and intake are clean, so I think maybe a flake of snow/drip of water was touching partially the MAF. One thing I noticed is that the SES light is gone since I did the intake cleaning and reinstalled everything -did the cleaning yesterday AM and did about 1hr of driving (mostly hwy) and since the last time it happened (2 weeks ago) the engine hesitation had not recurred.


Ramiro Munoz

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[Rammer'sX]

I think this issue was due to the faulty wheel bearing assembly. Since it was replaced, this has not occurred again


Ramiro Munoz

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