bad miss while crusing, never seen this before

[91tsirasinhell]

Ok for starters heres what is done to the car,

95 gst, 6bolt swaped
hard upper pipe
greddy type s bov
apxi avc-r
evo III GT 16G
act 2600 clutch

Anyway, after I put in the 6bolt the car started doing something weird. It runs fine till you get to crusing speed (55). Then after it stays there for a min it will start missing really bad. It feels like it is just on one cylinder, but I don't know. Then if you push in the clutch and let the RPM's come back to idle then get back in the gas it quits for a min then it will start back. If you are crusing around town changing gears all the time it rarely ever does it, but as soon as u cruse for a second it starts. It will do it occationaly in 4th, or 3rd gears but rarely.

I have changed the CAS, coilpack, igniter moduel, and none of them changed anything. I hope there is someone out there that has had this problem that can help me out.


thanks tyler

 

[lccynmbr13]

If you throw a CEL when this is happening it could be a simple fix. You didn't specify whether or not you were running the 6bolt/2g head or complete 1g 6bolt swap. Alot of people running the 1G CAS on the 2g head have problems with misfire codes. Since you say this happens when you're cruising and goes away if you make a sudden change in RPM there is an easy fix to the problem if I'm right in assuming you are using the 2g head. You just have to trick the ECU into reading less barometric pressure than there really is using a fairly simple mod. Check out this link from Magnus Motorsports it will tell you exactly how to do it. The part you need to worry about is toward the end of the page. http://www.magnusmotorsports.com/tech/1gina2g.pdf Let me know if that fixes your problem.

 

[calreef18]

I'm just tagging along here as I get missing on my 7-bolt when cruising on the freeway, nothing shows up on my data logger nor my rpm's or boost/vac gauge. Sounds similar to your problem, except mine does it only every so often, say on a 3 hour trip maybe 10 times. Sometimes it barely does it, others it kicks in a lot.

 

[91tsirasinhell]

If you throw a CEL when this is happening it could be a simple fix. You didn't specify whether or not you were running the 6bolt/2g head or complete 1g 6bolt swap. Alot of people running the 1G CAS on the 2g head have problems with misfire codes. Since you say this happens when you're cruising and goes away if you make a sudden change in RPM there is an easy fix to the problem if I'm right in assuming you are using the 2g head. You just have to trick the ECU into reading less barometric pressure than there really is using a fairly simple mod. Check out this link from Magnus Motorsports it will tell you exactly how to do it. The part you need to worry about is toward the end of the page. http://www.magnusmotorsports.com/tech/1gina2g.pdf Let me know if that fixes your problem.

It is a full 6bolt swap head and block. I am also using all 1g sensors CAS, coil pack, igniter moduel, and I have eliminated the EGR valve and silonoids . But I have read about that thing I thought it was just a fix to turnign the CEL off. I will try that tomarrow. But if anyone else has any more info it would be appreciated.

thanks tyler

 

[antlip]

In my 95 gsx I have a 6 bolt swap. I was throwing a check engine light everytime I got up to like 50 or 60. It would also of done it if I stomped the gas really hard. But i also have dsm link and didn't have invert CAS checked. Fixed my car right up by clicking that option.