Substantial loss of power? Especially right after shifting?

[mancheco]

My '86 2wd 2.5L auto trans MJ has just gone haywire. Had a pretty bad snow storm here in VA a few weeks back and I put my truck through the paces during that.. Now it's catching up with me.

 

Overall loss of power, especially right after it shifts. Strange back firing or popping noise occurs from time to time as well. Sometimes after the pop it will pick up and go for a while, but after I've got to stop and go again it will not want to get up and go. Pretty much a stretch to get it over 25-30mph.

Hoping someone will have to some answers to my issue or any sort of insight. I love this truck and have only had it for 6-8 months. I'd hate to see it go, especially right after finding this awesome website!

[Dave Stark]

Sounds like a bad vacuum leak...

[alleydog]

Maybe the cap is wet, from all the snow you may have gotten under the hood. Or possiblehigh resistance plug wire. Usually plug wires act up under a lugging load, and work OK at high rpm with low load. If it sounds ok at idle, put it in gear and hold the brakes and powerbrake it.Thats when a plug wire miss usually shows up. Just don't power brake too long, as the extra heat isnt too good for the torque convertor.

[mancheco]

Thanks for the quick replies. Worth mentioning the plug wires and plugs are fairly new. But I could see it being a bad misfire. I'll try to get a video of it up tomorrow, to possibly help pinpoint the issue.

Also I cleaned the filters in the oil breather cap the other day, and they were fairly clean, only to find that after this issue has started they are drenched in oil and there is some white cruddy stuff on the top of the cap as well.

[jeepcoma]

It's an unlikely problem, but you should check out the air filter. I had a similar sounding problem with an older Bronco II. After long highway trips in the rain or snow, it would lose power, pop and backfire out the tailpipe, and be a struggle to go 30 mph. Turned out I was slowly sucking water up through the air intak and it was drenching the air cleaner, and as it got wetter it would run richer and richer. After that, every time it rained I disconnected the snorkle that ran to the front of the radiator, problem solved.

[Dave Stark]

It's an unlikely problem, but you should check out the air filter. I had a similar sounding problem with an older Bronco II. After long highway trips in the rain or snow, it would lose power, pop and backfire out the tailpipe, and be a struggle to go 30 mph. Turned out I was slowly sucking water up through the air intak and it was drenching the air cleaner, and as it got wetter it would run richer and richer. After that, every time it rained I disconnected the snorkle that ran to the front of the radiator, problem solved.

 

 

:agree:

I had the same problem with a Wrangler that i rented on Hawaii. After i went through one too many low water crossings there was about an inch of water in the air filter box. I limped it back to the rental store, they were very apologetic & then gave me another one... :nuts:

[mancheco]

^

I'll check that out tomorrow. Big possibility, seeing as the air filter is less than a month old and almost looks like it is in need of replacing.

Again, thank you guys for your help with this.. Hopefully I can get my issue resolved. I'll post some pictures of her of tomorrow.

 

Edit:

Another thing is that it was driving normally at first, but halfway to my destination is when this all started happening. Issue was present the following day as well, though normalcy was never restored.

[87mjdriver]

what about a clogged fuel filter?

[Comanchero87]

here's another one. I have the same issue. Ive been searching this site for 1yr trying to find a topic that actually ends with a solution to this problem.

[cruiser54]

This tripped the old memory switch bringing back an issue we had at the dealership on an 86 4 banger. The guts of the catalytic converter had melted into a softball sized lump and would blow to the back of the cat and plug the exhaust. Symptoms were backfiring, low power. Then the softball must have rolled around a bit until the exhaust pressure pushed it to the back again. What a bear to find.

[Automan2164]

This tripped the old memory switch bringing back an issue we had at the dealership on an 86 4 banger. The guts of the catalytic converter had melted into a softball sized lump and would blow to the back of the cat and plug the exhaust. Symptoms were backfiring, low power. Then the softball must have rolled around a bit until the exhaust pressure pushed it to the back again. What a bear to find.

 

Yep, we have a gaggle of Chevy Impalas at work, and they actually have a recall for this. The Chief's car was having power issues. You could put it around town, but if you got on it, it would fall on its face and sound like it was really angry. It would snap and pop and sound like general hell. We ended up taking the o2 sensor out and starting it up. Ran a ton better. Then after a quick search on Google/GM VIS, we found out that the Impala has extended coverage for problems with the cat. Free fix.

 

Rob

[Comanchero87]

C101 connector/ ground harness modification/TPS adjustment. Fixed the problem. Just for the people who will search this and only find the question with no answers.