Ontiveros3

Due to my wife running a red light in our 91 400, I recently purchased a 96 400 with 193k on it. I recently moved 200 miles to Texas. Wife drove it with no problems. A few days ago, driving at around 35-40 it started bucking and loosing power. It would idle but very rough when you revved it up. And very rough in gear under load. After sitting a while and scratching my head I decided to un hook the battery for a few minutes. After re-hooking the battery it started right up and I was on my way. The next day short trip to the store it started doing it again. Only this time it wasn't trying to start and the battery trick didn't do squat. I cleaned up the IACV . Nothing! The only problem I saw with car when I bought it was a leak in the EGR tube.When this problem started it put out very strong exhaust odor. Any help would be appreciated.

LScowboyLS

sounds like a classic case of failing ECU capacitors - quite common known problem on 92-97 models especially - my 96 had this problem at 115K

but you can check a few other things first, such as, did you actually test that IACV off the car on a battery to verify that it steps to the 100 or so various positions, or even moves at all for that matter? - just cleaning it doesn't tell you that it is actually working - it could be locked up hard a rock with frozen bearings and yet now be very clean inside and yet frozen up!

Ontiveros3

I was afraid of hearing that. Not good. I cant afford to change it I would have to try and have the caps replaced. And thats not something I can do.How do I check the capacitors once I have the ECU out?

LScowboyLS

there are two ways, sometimes the leaking is obvious, as in the photos in my tutorial, or else you can do Yamae's ripple test as shown here