5S-FE Engine miss

[Tripleaj]

I have a 94 Camry with a 5S-FE engine (manual) in Oz which broke down on the highway. It started missing under acceleration, was OK after backing off, died again after accelerating, OK again after backing off and then completely died. I noticed a couple of backfires during the process also.
Got it home, found the coil arcing out so put a different dissy (complete with cap and leads) and the car was going again.
The problem is it is still missing on acceleration. I put the original cap and leads back on to no avail.
Decided to start from beginning and put the original dissy/cap/leads back on with a brand new ignition coil. The car is still going after hundreds of km's however the miss is still there on accel.
It is worth noting however that the car does not miss when it is cold and only starts once temp rises. Also there is no issue in the higher rpm range generally say above 3k.
I have done the diagnosis test (OB1 codes) and no errors arise.
As the car runs fine when cold and I have swapped and changed ignition parts, I am wondering whether it is a fuel issue?
Any help solving this issue would be appreciated.
Regards
Andrew.

[2win2rbo]

Have you replaced the fuel filter recently? This is supposed to be changed every 2 years. It's a must if you're filling up fuel in rural areas.

You can also have a look if the plugs are due or that they have the correct specifications.

[Tripleaj]

Thanks for the response.
The plugs were platinum and I have also tried a new set with no change.
The fuel filter is on the list to change as a good measure however as the car is fine cold and also is OK at high rpm, I feel it is not the issue. Will change tomorrow and see.
Thanks again.
Andrew

[Mike Gerber]

When cars run fine when cold and then have drivability problems when warm, I usually think of 2 things first.

One is the engine coolant temperature sensor which may be out of range and telling the car's computer it is still cold when it is warm. This would amount to a very rich fuel mixture for a warm engine. You can check the car's coolant temperature sensor with a digital volt/ohmeter and the specs from any manual. If you don't have a manual you can download one for free here:

http://www.automotiveforums.com/vbul...d.php?t=497839

Be sure to check the sensor both cold and then warm.

The other thing is the O2 sensor or sensors. (I'm not sure if your Austrailian version of the 5SFE engine uses 1 or 2 O2 sensors.) The O2 sensor is out of the loop until the engine reaches a certain temperature. A defective O2 sensor doesn't always throw a code on the OBD1 models.

Mike

[Tripleaj]

There is only one O2 sensor on the side of the exhaust manifold which I believe does very little and only help during cruise.
I have checked the Coolant Temp sensor which was OK. I removed the sensor, plugged the hole and re-connected the wire to the sensor to see how it ran thinking it was cold the whole time. This appeared to help on acceleration although hesitated a bit when I backed off under heavy accel. But there was a noticeable change.
I have replaced the fuel filter, sprayed the throttle body with cleaner and also had an on-car injector clean done.
Connected and plugged the coolant temp sensor back in and the car runs better but the problem still exists. On occasion the car stumbles at idle and fluctuated a little. Will remove throttle body next chance and clean everthing.
Any further responses would be appreciated.

[fenixus]

have you checked resistance of pins in o2 sensor plug? what do they read when cold (and what's the approx temperature)?

I don't see you checked the spark plug wires? perhaps they are old and cracked?

gen3 uses a distributor, have you checked the coil for hairline cracks?