P0300, P0303, P0305, P0130, P0401 codes, oh my!

[avalon-guy]

I have a 96 Avalon with 203,000 miles on it. I have had the timing belt changed within the last 10,000 miles. I have had these codes I have listed come up. Don't know when, or whether they came up at the same time or what.

I know P0300 is a cylinder misfire code as are P0303 (cylinder 3) and P0305 (cylinder 5).

P0401 is EGR flow insufficient.

Can all these be related somehow? Any ideas?

[Jack Deth]

how is it running right now? if it's running ok, i might be inclined to clear the codes and see what comes back.

[avalon-guy]

It runs fairly well. I also left out code P0301. So P0301, P0303, P0305 codes were all tripped meaning cylinders 1, 3, 5 were all misfiring. Since I also have a code for O2 SENSOR Bank 1 SLOW RESPONSE, I wonder if that is why all these cylinders on Bank 1 are misfiring.

[Jack Deth]

P0130 indicates that bank 1 is too lean. by itself, i would think O2 sensor. with all the other codes, though, maybe the sensor is working and you have a lean misfire.
if you pull the plugs from 1,3 & 5 and they are sooty, then the O2 sensor may be bad.
if they are "scorched" white, then bank 1 may be running lean. this may be related to the egr valve, the egr temp sensor, or a vacuum leak.
just guessing... i would suspect the egr valve or temp sensor. they ain't cheap, so do a little research and find out how to test or clean them before you throw money at them.

[comwiz]

I think most other error codes by misfiring. Check up the spark distribution wire from coil to cylinder 5, and coil 3. There are three coil.
---------------------
FIREWALL
---------------------------------------------------------------
1,2,3(distribution wired)
4,5,6(direct ignition)
---------------------------------------------------------------
CAR FRONT

coil1 = cylinder 4,1
coil2 = cylinder 5,2
coil3 = cylinder 6,3

This is cylinder numbering of your car. Red numbers are misfiring cylinders.
You have p0303,p0305 which are coil3 to indirect ignition, coil 2,and 3.

Today, I changed the spark plugs. I paid $40 for 6 of denso 3253.
A coil for 1mz-fe(which is your engine name.)is $55 , wire kit is around $33.
Change the fact of misfiring. Then clear the odb2 code. I think all the other error codes come from the misfiring because EGR(Exhaust Gas Recirculation) valve works with proper exhaust gas. If your car has misfiring, the EGR valve can't properly work.
Here are some stuffs I recommend you.

BECK/ARNLEY Part # 1788235

$54.79

BECK/ARNLEY Part # 1756153 PREMIUM; Diameter: 5mm; Black Wire; Mag Core 500 ohm/ft; Jacket Material: Blended EPS

$31.79

NGK Part # 7783

$33.79

Buy a kit of wire and a coil. $9x with shipping is not that expensive.
If you bring ur car to dealer, I think they will charge you more than $400, and local repair shops will charge you $2~300.