Sudden intermittent power loss

[damarble]

I'm having a odd issue that has me stumped. I'll be cruising along then suddenly there's a massive power loss as if I just hit a 40 MPH headwind. If I turn off the ignition and restart, the power comes back like normal. It does this erratically and without a pattern, but usually at least once, up to 4-5 times, during a 30 minute highway drive.

This is a 91 OHV with 5 speed. The CEL has never come on (yes, it does work).

 

[MrShorty]

I would probably pull codes anyway. The worst that you'll get is pass (11) codes.

I would probably also put a fuel pressure gauge on it. You might have to drive around until the symptoms show up to see what the pressure is doing when it loses power.

 

[CraigRK]

My bet, O2 sensor.
Easy check, just try disconnecting it at the pipe.
If problem dissappears . . . .

CraigK

 

[huntman58]

i would probably pull codes anyway. The worst that you'll get is pass (11) codes.

I would probably also put a fuel pressure gauge on it. You might have to drive around until the symptoms show up to see what the pressure is doing when it loses power.

x2

 

[damarble]

I'll give it a try.

What I don't get how just restarting fixes the problem.

 

[FIND]

try swapping the fuel pump relay for another relay, see if that helps you out any.

 

[stanleycr1]

What was it?

What did the problem end up being? I have one doing the same thing.

 

[damarble]

What did the problem end up being? I have one doing the same thing.

Dunno, haven't messed with it yet. Had to rebuild the front end and then drive it 1000 miles over a New Years vacation.

 

[Yerba1]

1993 Clean One Owner - ran fine until the transmission blew - replaced - and then the dreaded "safe mode" issue. Started last Fall when the temps changed. Unable to back up on any slight inclined - 500 yards later - it was as if the non existent turbo would kick in...So I tried replacing all of the sensors talked about here, new fuel line items, new driver's side 02 - and finally broke down and took it to my favorite mechanic - who charged me $290 for 3 weeks of on and off work. In the end - he ordered a used ECM (or the damned computer) for $90 from a local salvage yard - and problem fixed. Who knows what circuits we messed with over the course of the new tranny fix (the guys had to try 3 units before they found one that worked - who knows maybe ECM was almost bad then). Anyway - back to clean one owner - getting approximately 20 mph highway. Next up a knocking in the passenger ball joint.

 

[R&T Babich]

I'm having a odd issue that has me stumped. I'll be cruising along then suddenly there's a massive power loss as if I just hit a 40 MPH headwind. If I turn off the ignition and restart, the power comes back like normal. It does this erratically and without a pattern, but usually at least once, up to 4-5 times, during a 30 minute highway drive....

I have had 4 different vehicles over the years that developed a problem similar to these where you will be driving along and the ignition cuts clean.
Sometimes before the ignition would completely cut out there would be a couple of seconds of loss of power.
When the engine died I was going up a hill or accelerating from a stop.
In a few seconds or minutes it would start right up and run fine.
Each time it was the electronic ignition module (before computers).
One time the power supply lead to the module was almost completely broken.