I have a 2003 s type r. Had it for almost 4 years now. I've had problems off and on.

Coil issues being the biggest problem so far. I had 3 of them go out all about 2 months between each other so I finally just bought all 8 new ones so the coils and plugs have been changed within the last year.

I also probably 2 or 2 and a half years ago had to replace an upstream o2 sensor. I was pressed for money at the time so I only replaced one.

The problem I have now is the engine is still very obviously running roughly. Anything above half throttle results in a lot of popping and back firing. At lower rpms it shakes and makes a weird clicking/ticking/cracking noise. It took me quite awhile to figure it out but I think it's pinging and pre-igniting.

I bought a Bluetooth obd2 reader and downloaded the torque free program so I can monitor stuff on the car. One of the options is to monitor the 02 sensors. They never read the same thing. I'll have to try to find a way to post a pic or video of what it's reading but most the time one side will be .9 where the other side is reading .3 to .4

it will also tell me what my timing advance is. I've heard my car has like a 2 step vvt with the high step being like 44 degrees or something then a later version that could go to 48. Well when monitoring my car I found the timing to be going up to nearly 60 degrees sometimes. (Not even when full throttle) I have a very strong feeling this could be my problem....

I've done some research but can't find a whole lot on how it works or what it's based off or runs off of so now I'm here.

Also a slightly side note.... when having issues with coils I replaced the valve cover gaskets and all the o rings. I also visually inspected the timing chain and tensioners and there were no wear marks on them and looked totally fine.

As far as engine codes go... if I get on it kind of hard it'll be shaking then all of a sudden a huge jolt and restricted performance will be on with the engine light blinking. When I check the cel all it says is random misfire so that's not really much help.

I do have issues with restricted performance every once in awhile along with the engine code that means the pedal sensors and throttle body whatevers are not lining up upon start up. I've cleaned the throttle body as much as possible and it doesn't go off very often but it does happen altho I don't feel that it's related to the other problems.

Perhaps the only other thing is that I have the mufflers removed, the removal of the mufflers and the beginning of the current issues are probably a year and a half or 2 years apart so I also don't feel that that is part of the problem altho I do plan on putting mufflers back on to see if it changes.

So I plan to put the mufflers back on, switch my o2 sensors side to side to see if it's the o2 sensors or how the engine is burning (I don't think I'll find anythng) I also plan on removing all plugs and coils and change the cylinder they are in to see how much stuff changes.

any help or suggestions would be great, especially on the vvt stuff. I honestly don't even know if it's an electrical or hydrolic system. Thanks in advance for the help

 

Ouch! PLEASE USE SOME FORMATTING!!

Your car (like mine) has no VVT.

I gave up trying to read all the mess you posted.

 

The only info I could find on it was:

"The engine originally used a two-state Variable Valve Timing*system to switch the intake cam timing by 30°. Newer variants use a more sophisticated system which can vary intake timing incrementally up to 48°."

Sounded like to me that they all have it altho to be honest it always kinda surprised me that the supercharged models had vvt.

 

Properly operating 02 sensors oscillate up and down. I believe Torque has a graphing feature that you can use to monitor them.

 

You can read the proper details in brochures, manuals etc but the 2003 STR does not have VVT.

 

Looked at the torque program again and it was timing advance that I was looking at not not valve timing. I suppose I kinda made a fool of myself there but it kinda made sense that valve timing too far advanced could act this way.....
anyways....
I'm out messing with the car now and ill have a pic of the o2s up shortly.

 

 

 

 

So.... looks like my 2x2 is not working well. I imagine it would be worth while switching o2 sensors side to side to see if the changes are consistent yes? Or just that sensor needs replaced?

I know that when some of my coils were having issues I was getting codes for the o2s but there was nothing wrong with them. They were reading the extra gas going thru the exhaust from the dead coil so it kinda lead me in the wrong direction. Just thinking if this could be another of those situations. I know I drive a jag and all but o2s aren't exactly cheap

 

Spark plugs drivers side (us)

 

You need to check your catalysts, if they are choked up the engine will run poorly and misfire, detonate and generally be way down on power.

I've been through this with my XJR. The catalysts don't last forever.

 

The catalytic converters in the exhaust? Exhaust doesn't smell like it. At least not the traditional smell. Any idea on how to test? Could I remove them and measure resistance trying to push air thru them or anything?

 

It does have 143000 miles....

 

Passenger side. Second from the right looks kind of weird. I also noticed on the previous picture that the second from the right looks like it has not been firing as much.

 

OEM Denso O2 sensors from Rock Auto are a reasonable price.

If it's 143'000 miles on the original cats then yeah, they won't be at their best... the pressure drop through the cats can be measured by an exhaust shop, plumb in pipes to the O2 sensor ports upstream & downstream, and measure the differential pressure.

Those plugs don't look too bad to me, if they are less than a year old then that explains why they look so new.

 

They are probably right around a year old. Just called the shop and they said that the original equipment was double platinum and said autolite, Delco and one other brand made them. Price range from high 4s up to like 7 I think. I have the ngk iridium which is listed in their computer for this car but aren't the same double platinum that oe was. Think this could be a problem. I know some cars (jeep wj) from past experience NEED specific plugs.

 

Turns out bank 1 is the original o2 sensor and bank 2 is the one that has been replaced within the last 2 years.

The pics I've posted were just in park, I didn't drive anywhere but it only makes the weird noises and stuff while driving so the next pics are while driving....