Rough Idle

[abew330]

Rough Idle

well after a long drive yesterday my car 94 Camry 1mz start to struggle under acceleration also very very rough idle. At first maybe i thought needs a tune up.

So today I made a trip to local parts store and started the tune up on the car
changed:
air filter, fuel filter, spark plugs valve cover gaskets oil change with new oil filter, removed the whole TB and cleaned it out, also cleaned a little of the intake.. Notice what seem to be a little build up of black sh*t on the egr so I attempted to clean it but decided to leave alone...

After I changed everything it started fine but after 5-7 mins it started rough idle again…

Maybe 500 miles earlier I did a seafoam which went Very well. Before the seafoam I had terrible MPG. Around 200 miles to a full tank... Now After the seafoam I get at least 85 – 115 miles extra (total of 285 – 315 miles) to a full tank.

Basically at idle/ stop very rough idle. Once above maybe 1500 RPM it rides ok...
I started to notice when the engine is cold the idle is fine. (Not rough)
Once the engine is warm, the engine seems to start and stop from idle normal and rough idle

Edit** I just started the car and its “cold” and started rough idle

Also something seems to be turning on and off. Took the car out for a drive and notice every other red light I passed the car would switch from rough idle to normal idle…

Any ideas, what to check, advice, 2 cents very appreciated

thank you in advance

[Mike Gerber]

1. Check for vacuum leaks.
2. Clean the throttle body and the idle air control valve.
3. Inspect/change the spark plug wires, distributor cap and rotor.
4. Check the coil inside the distributor for being in spec and also check it visually for hariline cracks. You will need a digital volt/ohmeter and the specs from any manual to do this.

It would also be helpful to know how many miles on the car.

Mike

[abew330]

i will check for vac leaks today.

the TB was cleaned. the IAC is just below the TB correct? i removed whole TB but none of the parts below it. i just cleaned inside of the TB

no spark plug wires.. change spark plugs... my car is Distributorless.

sorry the miles is about 217XXX

Mike Gerber, Thank you for reply!

[Mike Gerber]

"my car is Distributorless"

My error. You are correct. The 4 cylinder 94's still used a distributor.

When you cleaned the throttle body did you spray any of the cleaner down in to the square or diamond shaped hole in the base of the throttle body? That hole is a port leading to the idle air control valve. If you didn't, just remove the big tube leading to the throttle body now and spray some throttle body cleaner or O2 safe carb cleaner liberally down there and let it soak for 10 minutes. Then reconnect the big tube to the throttle body and start the car. Take it for a 10 minute ride. See if that helps.

Mike

[abew330]

hey Mike, i un-bolted the whole TB today and cleaned at every hole on the inside of the TB.
after cleaned i re-connected everything back and it started up but just after starting it still had the "rough idle"

note: rough idle is Now present during driving / at stop/ idle

[abew330]

update:

i somewhat came to a conclusion its has to be a mis-fire

while checking the 3 easily accessed coils on the "front" side of the engine
(not the coils closest to the firewall)
i believe the 6th coil is not firing. so i swap out that coil with known working one.. still same problem..
so maybe i though it was the Ignition Control Module. swap that out.. problem still persist.
now i checked connection at ecu maybe dirty connectors. nope...

any other ideas what to check? past experiences? anything... i would really appreciate


edit:

while driving check engine light blinks/ flash 15 times first then maybe 4 mins later 12 times

[Mike Gerber]

You need to read the codes that are present. You can do that with a paper clip or a piece of wire. The procedure and what the codes mean will be in any manual. If you don't have a manual available to you go over to the Camry forum over at AutomotiveForums.com. There are Toyota factory service manuals stickied at the top of that forum that are available for free downlaoding. Download the generation 3 manual. Report back here with the codes and someone will be able to give you some direction.

Mike

[abew330]

for some reason when i connect to DLC1 using a wire from TE1 to E1 the check light does not flash...

got all the pdf for gen 3

now idle is high and still rough

[Mike Gerber]

Check under the dash for an OBD2 connector. Some of the 94's and the 95's with the V6 engines were already OBD2, even though it wasn't required until the 1996 model year. You may be able to read the codes with an OBD2 code reader.

Mike

[abew330]

Update*
ok got the computer read yesterday and it gave me 3 codes

PO174
PO306
PO206

so come to find out the injector over the 6th cyl was bad
i got a another injector replaced it and the car runs way better now.

[Mike Gerber]

Glad you got the problem solved. It looks like your car was already OBD2 compliant. You were on the right track when you concluded it must be a missfire. The P0306 code is a missfire on cylinder 6. The P0206 is an electrical fault on the number 6 injector and the P0174 is a system too lean on cylinder bank number 2. These were all because of the bad injector in cylinder 6. Well done.

Mike