My 1981 GL wagon is suddenly displaying a lack of low end power. It's completely stock, except for an MSD ignition. New plugs and wires last year. It runs decently, though always was rough till it warmed up. 240k on it, so everything's pretty old... The last two weeks we've been driving it a lot more because of the floods -- it handles the mud and bad roads a lot better than the prius It just started having issues and running out of power if you try to accelerate under 2000rpm. Above 2000 it still seems okay, but under, it seems to drop off very suddenly. There's one hill on a jeep trail that it used to happily crawl up in 1st low, or zoom up in 1st high if you gave it more gas... now you have to keep the rpms up at 2500rpm or more in 1st low to even get up it, and no chance of getting up in 1st hi. Also, an odd smell when it bogs down... kind of in between fuel and something getting too hot. Ideas on what to check?
Another possible symptom is a lot of backfiring in the exhaust when going downhill under engine braking. It always used to do this some, but it seems like more now. Though not as bad as my '76 ford courier pickup... that backfired so bad in the exhaust that it split the muffler apart.
And, I went through a big stream/puddle about a foot or a little more deep, and it wasn't happy.... wasn't water in the disty which is what I suspected, but the idle got really rough and it really lacked power for a minute or two after that. But... I went through the same puddle three more times, and it was okay those times....