nthach

I've been noticing a little bit of a stumble around 1000-1500 RPM lately but the car runs fine above that. But yesterday I noticed a little misfire at idle, and tonight as I drove home I suddenly lose power, and the engine was running rough. I managed to limp home, and I noticed smoke pouring out. So I check the coils, one of them doesn't check out, the other is above Toyota spec for primary resistance. And yes, I was able to smell raw fuel in the exhaust.

So I know a lot of attention is being made about bad caps in the ECU - and I probably should have someone recap it. But for coils, should I get the OEM one or will a cheaper aftermarket one work fine for our cars?

PureDrifter

iTrader: (10)

oem or big name (denso, ngk, etc.) replacement will be fine.

Shmee

iTrader: (3)

If the coils tested bad, I would replace the coils before you dive into the ECU.
While that seems to be flavour of the day for all things gone wrong in these cars, the caps in the ECU are not going to fix hard part failure nor is it likely it will cause a hard part failure.

Always follow the diagnostic protocol. if you test a part and it's out of spec, replace it first and retest.
if you still have a issue, and the part is testing good, move down the diagnostic line until you have solved the the root-cause of the problem.

If that leads you to the ECU, then by all means replace the caps and retest.

skipping right to the end and replacing at the caps can often mask issues and faulty hard parts through adaptation systems.

i'm not saying the caps are not an issue in these cars, just don't jump to that conclusion. We are dealing qith 12-20+y/o cars here, many with exceptionally high mileage... there are going to be a LOT of faulty hard parts to replace. Most cars parts have a typical average life of 8-10years or about 100k miles max, so always test before you replace unless you are doing preventative maintenance.

nthach

I'm confident it's the coils first. I'll replace them both with Kragen/O'Reilly ones that have a "lifetime warranty" to get me by. While one is bad, the other one can't be too far off. And I'll also install a new filter and take care of some PM as well.

trukn1

New coils are often the culprits with the symptoms you describe above, and they are fairly easy to get to and cheap to fix. Gotta remember that these cars are now startign to get some age on them, and things like coils are most often overlooked in it's replacement.

nthach

So, i swapped in the new coil after pulling the driver's side coil and the engine didn't kick over. Same result, rough idle and raw fuel being dumped. I took off the spark plug covers and I found a charred coil wire on the RH distributor, the wires were Denso aftermarket ones, which aren't sourced from Sumitomo or Yazaki. It's off to Carquest after work to get a set of NGK wires.

Shmee

iTrader: (3)

If the coil wire is charred, have a good look at the wires and the plugs. If you're getting raw fuel out the pipe, you probably have some rich-fouled plugs.

nthach

2 plugs were black, but not fouled to oblivion. I cleaned up one of them, and the other looks like it'll be OK when the car is running at temp. The car initially hesitated to start but it turned over after a jump start.