mynameisgaven

I have a 94 civic dx 1.5l d15b7. I recently swapped a tranny from a civic at the junkyard. After it got swapped, the car started running weird, the tranny felt fine it shifted into every gear no grinds. The car when its idleing is at a really low rpm(i dont have a tachometer but i can hear it), low enough that itl stall sometimes. at the low idle, the engine revs are going up and down sounds kinda in between 800-1000. When im driving the car hesitates, like itl stutter then pick back up. I doubt that its the tranny. I'm replacing the distributor cap tommorow. What else could cause this.

mynameisgaven

Also the fan in front of the radiator stopped turning on. Its the one thats not controlled by the switch inside the car. The fan itself still works, i tested it by redirecting itself with a paperclip, so what could be the problem?

Vtec Rebecca

I had a similar problem with my 94 civic vtec, but it happened after exhaust pipe broke right before muffler. Per my most trusted advisors, it was the heated o2 sensor in the exhaust manifold. Apparently the sensor is similar to a light bulb with a filament that when jostled hard enough can break. I replaced it and it ran fine for 2 weeks, now its doing the same thing and throwing a #1 code which is o2 sensor. Need to fix exhaust properly and replace again, but thats my problem. You may also want to clean your iacv as I did and it was very dirty, also helps with idle issues. Also, the fan relay in the fuse box is most likely bad for your fan issue.