Rough Idle Solution ( The hard way)

[outthere2]

1999 Camry V6

I had a rough Idle at 750rpm.The car would intermittently dip down to 500 then back up.
The problem also made the car seem sluggish when pulling away.
I tried to find a solution in the Forum but couldn't nail anything down as the cause.

Things I tried.in order.
Replaced EGR Valve.
(Still Rough Idle)
Took the car in to see if there was a stored code in OBD.
( Code came back as a cylinder # 4 missfire)
Bought a new coil pack and replaced #4.
(Still had rough Idle)
Brought car back to dealer and rechecked OBD codes.
( Multiple missfires detected)
Replaced Oil/Filter ,Air Cleaner, Spark Plugs.
(Ran well for two days then back to rough idle)
After more digging I replaced Bosch plugs with NGK
( OK for two days then rough idle again)
Found that IAC (Idle Air Control Valve) gets sticky on this model, from the Forum,
so did a complete dismantle of the Throttle Body and cleaning with Sea Foam spray.
Sea Foam does work very well for Carbon buildup along with a tooth brush.

The dealer here in Cambridge was very helpful.
The car was taken in for diagnosis again by my Wife andthey again identified the #4
cylinder.This pointed me toward the spark plug wire.
The parts guy threw me off this part early on saying that he hadn't ordered one in 2 years.

I also asked the mechanic if the coil maybe had an adverse effect on the wire and he said yes.

So to make a long story short the #4 coil was bad but leaving it for so long wreacked the
spark plug wire.

I hope this info will help someone else.

Outthere...

[InstallTech]

Wow. I can sure sympathize with you on that one. Took me about 6 months, multiple trips to different shops, many phone calls, about 300 dollars in parts to find out that my problem on my 93 Camry was a $40 faulty ignition coil. Glad you were able to get it figured out, though.

[ice745]

I've never really had problems with Bosch spark plugs, but I really advise against using their spark plug wires. I don't know if thats what you got, or if you've ever had any luck with them in the past. I got them one time, and after a few month I had to check the spark plugs because the engine was running a lil weird. Little did I know the trouble was only going to begin there. When I went to take off the first spark plug wire, the grip handle came off of the plastic boot, and started sliding up the wire. Then I tried to put it back, but it wouldn't stay on, so then I tried using pliers to grab the plastic boot and pull up, and VOILA it came out...and by it, I mean the plastic boot and ...most of the wire... The metal connector at the end was still on the spark plug, which was just long enough to prevent a socket from unscrewing the plug. After a few hours and some cursing off the car by my neighbor, we finally got that one off. YESSS! Then the second cylinder. And of course, same thing, same exact thing. At the end of the day, I was thanking god I got the 4 cylinder model and not 6. Then I ordered Borg/Warner spark plug wires, and they seem to be built A LOT better.

[marc780]

Ice i always try to use a dab of dielectric grease on the plug end/plug wire to help it not seize next time (and anti sieze on the plugwire threads). Also try soaking them with silicone spray and use plug wire pliers to get off the cable