donkita

'99 ES 300, 200k miles. Riding down the interstate, the CHECK ENGINE and TRAC OFF lights come on, and the car starts running like crap. Pull over and reset the ECM. Purrs like a kitten for a couple of miles, then it happens again. Went by the mechanic to check the codes, and the rear cylinders, 2, 4 and 6, are misfiring. He says the coils on these may have fried, but I call BS because I can reset the ECM and they work for a while. Checked the plugs and wires, and they look fine. Would appreciate any suggestions on what to check. I'm a decent wrench, but not so good at diagnostics.

BoostedE21

In fairness to your mechanic, when my car did the same thing, it would run decently if I reset the lights and then start crapping out a few minutes later. Replaced the coils, and no problems.

I have three good coils that I can sell you for pretty cheap, if you want to give those a try before you start replacing the expensive stuff.

QuachmanES

iTrader: (4)

Same exact thing happened to me last year. Check engine and TRAC lights on, reduced power, and a rough idle. I had to replace the coils on the rear bank (2-4-6).

03 ES

could be bad coils or spark plugs....have you ever changed the plugs?
start with plugs if you havent changed those...always start with the most inexpensive items first.

donkita

Alright, I'm willing to be wrong about that. I did change the plugs about 2k miles ago. Mechanic says the change in resistance of the new plugs can fry the coils (I just don't understand why only the rear cylinders). Anyway, If you will PM me price and payment info for the coils, I will try that. Thanks for all responses. I feel better about this already. I was thinking ECM malfunction or possible HG.

donkita

Okay, tried replacing the coils; same problem. Took it to Toyota dealership for diagnosis. Was told the misfires were most likely due to VVTi sensor code that was showing up. Quoted approx. $500 to replace. NAPA shows camshaft sensor for $124.00 (P/N DEM SS10502). So, is this the part I need?

donkita

Alrighty then. Thanks anyway. I found the part for $75 at Rockauto, so I'll give it a try.

donkita

I've replaced the coil packs. Same problem. Took it dealer for diag. Said it was showing code for VVTi controller, and I should start there. I replaced the VVTi sensor (I'm assuming "controller" and "sensor" are the same). Same problem. So, does anyone have other suggestions? Is this the state of modern automotive diagnostics? Just throw parts at it until something works. If so, I think I could be a fairly profitable mechanic. I mean, seriously, this is what the dealership said would be their first step. So I would have paid $500 for a $100 part that didn't fix the problem? Obviously, I'm frustrated. Any help would be appreciated.