50% drop in mpg linked to not releasing gear while stopping
I have an intermittent issue.
My mpg cuts in half after about 1/2 of driving, sometimes only after 2 minutes. Another connected symptom is that when coming to a stop the car won't shift out of gear and sputters and tuggs until I stop fully and the car rocks back (then buttery smooth).
What controls both these things? Computer? They only happen together.
I thought the hole in my manifold was causing a poor mileage issue until I noticed I was getting 15-24 depending on hills. In an instant it will drop for the rest of the ride to 8-12. Same amount of push on gas pedal, same hillls.
Overall average for last 1k miles is 10.2 mpg. Ouch!
everything is computer controlled.
there's a lock up solenoid, its normally closed operation. when fluid is vented by the noid the converter locks up. if changing the solenoid pack(the od solenoid and tcc solenoid are on one pack and it's kinda expensive) doesn't fix things the converter is fried.
a converter stall test will give you a good indication of health on the converter.
'97 zj 5.2, some stuff, some other suff, and some things that even work sometimes.
I'll do it next time I leave the house. Here are my thoughts on it...
If my torque converter was responsible for a sudden drop of 20mpg to 10mpg on the highway, wouldn't I feel it slip, jerk or the rpms would raise? When the drop comes, nothing happens in the drivetrain. How would Torque Converter issues affect MPG without me feeling it?
Example: I leave the house, drive through town, everything is buttery smooth. I hop on the highway, 10min down the highway my mpg drops by 50%, other than that nothing has changed. I hop off the highway 10min later and when I slow to a stop the car won't shift out. If the gas mileage is poor the car always has TC issues.
Ok I will put this thread on hold for a few days while waiting for my exhaust manifold to get here. Start with that, drive a bit and see what I get, then unhook the upstream o2 sensor depending on results. Then post findings.
Will also do a TC stall test when it's running well.
TC stall test was 1750rpm in Drive and Reverse assuming I did it correctly. That is when things are running correctly. If I get the intermittent issue again as I suspect I will, I will post another stall test with the car running poorly.
Installed the manifold today and we shall see how it affects the mpg in the next few days. I will post with more info.
Noticed this connector had no home... any idea where it goes?
It is part of a bundle of which the thickest of the 3 goes into the brake booster. The skinny one drops in behind the master cylinder and connects to an unseen place, and this one is the medium size one that goes?..