Here are the codes:
P0351 ignition coil
P0352 coil
P0353 coil
P0354 coil
P0355 coil
P0121 tps

All those P035# are ignition coils.
The P0121 is the throttle position sensor

 

Try swapping 2 coils out with the old ones you got and check if your codes go away

 

I don't have my old coils anymore since I changed mine 5 months ago. College dorms won't let me keep stuff so due to circumstances I had to throw it out.

 

How is the wiring to the coils? Make sure nothing is pinched. Make sure the connectors are in tact and clean.

The throttle code is generic. There are likely other codes stored. I'm not sure a software reload will help. You may need a new throttle or a rebuilt one.

 

I have replaced my ETM with a used (newer and cleaner) ETM.
Both ETMs (old and new) shows the same problem. One of the reason why I bought a different ETM was because I assumed the ETM was the cause. but it didn't change anything.

I checked the wirings earlier this morning to make sure nothing is loose or pinched but I found none that particularly sticks out.
I even unplugged a few of the coils but it made such a slight difference to the rough idle.
I'll try uploading a video of me taking off the ignition coils one by one.

I'm getting more and more confused and frustrated at this car (I'm at Pensacola, FL, there's only one Volvo dealer and that dealer cost me an arm and leg to fix things)

 

Yes, I know you replaced the throttle with a used one. That just means you have a different throttle, not a good throttle.

The dealer may be expensive and I know you're on a budget. But guessing doesn't usually help budgets either. Dealer diagnosis is free and better than the kid at the parts store with his code reader.

 

Oh I'm sorry, my bad I just didn't get it the first time since I was at work earlier.

I'll call the local stealer tomorrow and ask about the free diagnosis. If you can't tell already I just have a bit trauma with dealers. (Spent almost $800 to fix my ignition lock cylinder)

 

If its Centennial, the info on free diagnosis is on their website.

 

Misfire on all coils.... ok check the ground on the cylinder head yea that and engine block have separate grounds... It is located behind the cylinder head on the passenger side - unscrew the contact and clean it an just put another extra ground wire there that has good ground contact - just leave the old one where it is - can never have too much ground

 

yes I saw the complementary diagnosis. Gotta tow my car there since it's in limp mode and don't want to add more problem.

I'll try to check the ground wire and see if there's something out of the ordinary. thank you for the advice. I'm checking it tomorrow. Any advice on how should I proceed doing this? (unplug battery, easier way to maneuver around, or other tips?)

 

No not rly bc it is the - ground wire and + is not involved just make sure the new - wire has a clean connection to the new ground (chassi)

 

Checked the ground wire and none of them is broken/loose/missing

although I found out that my MAF didn't not turn of my car when I unplugged it. I have a strong assumption that my MAF has something to do with all this.

 

It's not the ground. The codes are for open circuit or short to ground in the primary coil circuit. The wiring between the ECM and coils needs to be checked. By far, the most common source of issues there is pinched or damaged wiring on top of the engine, which is why I mentioned checking that.

Are the coils used like the throttle?

The car should still run with the MAF unplugged. You have a strong assumption the MAF has something to do with this, based on what? The codes don't point to it. The symptoms don't point to it.

 

I am not talking about the 3 ones bolted to the chassi on each side of the motor but the braided wire connected to the cylinder head block - did you check that one ?

 

Using a DMM just check it

 

Yes the thin but wide braided wire. Check do gunks on the connection. Followed the wire to see if it's connected and all. Nothing seems out of place.

What still doesn't get me is why did all this happened after a fuel filter and MAF? It wasn't like this prior to those two replaced.

Thank you for all the replies though. It's a great thing to be able to share and brainstorm about this.

 

You say it wasn't like this before the MAF, but yet, you replaced the MAF for a rough idle.

A MAF isn't going to set the codes you have.

 

Can you get a used COP from the junkyard and test if that one gets a error code ?

The COP you replaced are they used or new ones ?

 

They're new but aftermarket. And they were doing fine until fuel filter and MAF.

 

Ok check if the fuel filter is installed correctly ie the arrow on it should point towards the engine - If it is installed incorrectly you need to change it out for a new one bc otherwise you will get dirt/particles into your Injector that can cause you other problems