This is an issue I've been having for awhile and I could really use some help pinpointing potential issues.

This seems to happen when I'm in fifth gear at ~2400rpm the engine sputters and shakes the car, as soon as I'm at 2600rpm I'm fine. To me I'm thinking timing chain potentially? But I'm not really sure. Please note this began happening long before any modifications or tune but I've simply worked around it by reving 4th to 4000rpm and shifting there (never hit 2400rpm lol). The throttle position is around 15%, below 10% this doesn't happen and is progressively worse the higher the load. (Yes like lugging the engine, but keep in mind this is above factory recommended shift point for fifth which is 45mph or ~2000rpm).

Before I go inspecting my timing chain (I heard the case is a giant pita to get off) does anyone else have recommended checks?

 

Im having something very similar happening on my 8, but completely random, does yours happen consistently?
Heres my thread if you want to compare.
https://www.evolutionm.net/forums/ev...-cruising.html

 

Interesting! It's a bit random but if we went on 5 runs and I was really trying, I think I could reproduce it.

 

This is just my thoughts but im not 100% sure here..... I thinking if it was the chain you would have a few spots that would be doing this in the RPM range/gears however like i said im not too sure

Here is the list of things i would check first...
1. Have a tuner ride along with you have look at the fuel tables at that given chain of events, you could have a lean spot in your Fuel table. Even at stock, the ECU will learn in given evens and make corrections to the map (fuel tables, timing ect ect). however if your fuel map is jacked to start, it will always be off a bit...
2. If you dont have a tuner that can do that, try and hook up an AFR gauge and see what it tells you at that time. rich or lean, that will tell you that you have a bad spot in the fuel table or should give you a hit as to what the ECU is doing..
3. change out your Fuel relay (I believe you can just change the horn and the fuel relays as they are the same for a fast check.
4. check to make sure your Fuel pressure reg hose is still attached and free of any cracks... this is the little hose that goes from the fuel rail to the regulator. (its located on the passanger side of the fuel rail under the engine cover) if you dont have zip ties on it already, PUT THEM ON
5. this one is kinda stupid but its a free check... pull the battery for a few hours.. you will have to redo your radio but these cars are very much like computers now a days and as a software engineer i can tell you that someone just hitting the reset button can fix the craziest stuff. Pulling the bat for a while will reset to ECU to a point. its very similar to people that pull the bat to clear codes that they know will go away like leaving the gas cap off or something.

once again this is just my 2cents on what i would do first before taking the car apart LOL.

Good luck and please let us all know what you find or how you fixed the issue. A lot of these threads are dead ends b/c everything is so happy to have fixed whatever issue they may have and forget to let us all know what went down LOL

 

Thanks for the reply!

I've sorta done most of these already, though I think getting a tuner in might be a good idea.

- My AFR gauge doesn't reveal anything weird (though I still need to solder together the 9 pin RS232 to it and hook it up)
- Fuel Relay is the Panasonic Orange changed about a month ago
- This is one I haven't done and I have cracks appearing in the powersteering lines so very well a huge possibility.
- Lol it's been getting disconnected for long periods these days but yeah, when all else fails, give it a swift kick in the rear has been my solution to server issues at work for quite awhile.

 

any luck?

 

I don't see any fuel leaks, but I decided to rub salt into the wound by tossing a can of seafoam into the fuel tank only (seafoam does a super good job at cleaning, this includes cleaning gunk holding the place of old gaskets lol). I'm trying to aggravate the issue, I'd rather make it worse to detect and fix it instead.

Seafoam, I've aggravated something, I'm getting a bit of ... kick back... and a rougher idle since running it through so I'm going to get it up on a lift and let it idle to see what I can find.

Pulling the battery had made no difference (I pulled it for about 10hrs).

 

Might be time for some ID1000s! hope you can figure it out

 

Spark plugs! That's the ticket for mine. Was doing routine maintenance and the issue went away. However where on leaves another one appears, pulled the spark plug in cylinder #3 and there was oil on the business end (the spark end). Compression test incoming, I'm hoping I don't have to pull the whole darn thing till summer, my summer bonus was planned for some manley i beams (rarrr).

Welp, we'll see, hopefully between now and then I don't scratch my cylinder wall because I have to keep driving it for now.