This is just odd..your misfire switched from an entire r/s bank to the entire l/s bank?? You definitly have more than one issue here...
First thing I'd do is a visual inspection of the engine area. Inspect including looking at the ox sensor plugs for oil ingress also unplug them and check for corrosion), inspect the knock sensors (especially bank 1) to see if they are melted and replace a necessary, check engine harness routing for rubbing, shorting and melted wires around the upper intake plenum area or on the back of the cylinder heads,check for coolant leaking on the cankshaft sensor. A fuel pressure check and cylinder compression test is also in order here. A scan tool capable of reading the ox sensor outputs would also help.

It's kind of tough for me to recommend replacing the head gaskets first even IF they are leaking. I think you find you still have most of these issues afterwards. Go back to the basics and start there.

If your mechanic has already began to tear down for head gaskets. make sure he inspects the camshaft lobes for wear, checks the heads for warpage. and checks the valves to make sure they're not sticking in the guides.

Cheers

 

Reading back to your first post i cant tell if you had the misfires before or after you replaced the spark plugs. If it was after the plugs replace them with some inexpensive $1.50 champion platinums they are the best.

 

Thanks for suggestion. I have already bought Champion platinums and will replace it after i will find out what causes misfires and after checking engine if there is something wrong with it.

 

So, finally engine was taken into parts and all valve seals were burnt and almost all gaskets needed replacement. After polishing and cleaning engine, it looks like this.

i did all head gasket job and replaced all gaskets and seals, installed new knock sensors (Standard Motor Products) and new Champion plugs. I also checked the engine for any cracks and it didnt show anything. The water

At least after its assembled and engine starts i will definitely know that with engine everything is ok. And if it will be still powerless, not idling and accelerating well, then i will move to transmission problems. Wires and O2 Sensors are newly replaced and i didnt touch them. Ignition coils are also working well. Before taking apart, car was idling normally on neutral and parking position, but directly after shifting gear in D, it was stalling, shaking and didnt have any power. Codes were misfires, O2 sensors, knock sensor, 1300, 0172 and 0453.

Will update information as assembling imho will be finished in this week.

 

So, after full engine gasket job and assembling back, it is still throwing up codes and not accelerating and has no power. It shows misfire on 5th and 7th cylinders and also random misfire. I checked again and as mechanic is saying the electricity is coming normally from ignition coils and wires, so now he is advising to clean fuel injectors as they might be the cause.

I dont know, I am kind of suspicious about cleaning fuel injectors. what are the possibilities and what can it be? I have checked and camshaft is working perfectly, there is no leaking oil or coolant, it just misfires and gives flashing SES light even in Parking position and car is shaking when its idling.

I replaced spark plugs and they are new. Plug wires are also new and they are working perfectly. I also replaced both knock sensors and scanner does not throw up knock sensor codes.

I am already lost and have no idea what to do and how to repair it. I would really appreciate your suggestions of possible causes of misfires and loss of power and how clever is it to clean fuel injectors?

 

Verdict?

 

So, its been already more than year since I wrote the last update. The verdict was blown head gasket and burnt valve seals. After head gasket job, the idiot mechanic forgot to connect O2 sensors and thats why it was not idling and running well. I found it myself, connected and since then car is driving perfectly. No major issues came up, replaced only Crankshaft position sensor last winter.

Recently, it started to have some small problem. Thing is that, on uphill, while accelerating its running normally, but once i stop acceleration, the SES light flashes and throws several codes. It throws O2 sensor codes, but have scanned with live data and O2 sensors are working perfectly and mixing air/fuel well. The main code is 0305 and 0300. During flashing SES light, car is not losing power and accelerates normal.

As gasket job was done recently and i dont have any oil/water leaks, i am supposing it to be the problem of coils. During head gasket job, i have not replaced coils. I checked all spark plugs, all of them looked same way, normal wear. At night i checked wires, saw some flashing on several of them, but not arcing. Wires are flashing near spark plugs. Could they be going bad? I have kingsborne 8mm wires which i replaced several months before head gasket job was done.

Before replacing anything, i am going to make compression test myself and could you please write what is the easiest way to disable ignition? i will pull out fuel pump relay, all plugs and wires, but how to disable ignition? Also, what is the normal compression range? I am thinking something around 150-180 psi.

Write, if you had same experience, or might now what might be causing such misfire, without losing power only on uphills while stopping acceleration?

 

any suggestions what might be the problem and how to disconnect ignition?

 

"At night i checked wires, saw some flashing on several of them, but not arcing. Wires are flashing near spark plugs." This should never happen start by checking and or replacing those wires.

 

Finally I got compression tester and tested engine compression today with fear. Fortunately, all cylinders were in a range of 170-180 psi. I am excluding any head gasket or valve job and will just make tune up with plugs, wires and coils.

i have been searching here how to make compression test properly, but couldn't find full guide, so will write here what I did and how I did it.

1. Checked the battery with multimeter if it was fully charged. Normally it should be around 12+;
2. Took out fuel pump relay (which is in the fuse box under the hood marked R1);
3. For driver side plugs, was better for me to disconnect MAF sensor hose from throttle body;
4. Disconnected all plug wires and took out all plugs;
5. Measured compression of each cylinder twice and wrote them down according to cylinders; and
6. Finally, assembled everything back.

Will order Champion plugs and Kingsborne wires and will update information after replacing them.