Ok, the basics first:

b18c5 motor and tranny with 4.9 final drive
obd2 wired car with obd2 to obd1 harness and p28 s200
toda spec c cams (@ 0,0)
hytech header
short ram intake
2.5" mandrel exhaust

Street tuned to 13.5-14:1 with wideband.

The cams idle at columns 5 and 6 instead of the 1-2 range where the stock cams idled.....very low vacuum at idle.

The idle we kinda got worked out by advancing the timing and leaning out the fuel from a tuned itr cams map given to me by a friend.

But we couldn't get the lurching to go away on the hwy...

This is cruising between 3800-5200 rpms - which is 65mph to 85mph roughly in 5th gear with my tranny and final drive. I noticed this is between 1 and 10% throttle. It happens a lot between 2% and 6% throttle just cruising at those rpm/ mph.....

What should we check to get rid of this "stumble?"

It is quite annoying.

And if anyone has a stock itr motor with spec c map, please send it to me!

 

have you been able to check what your A/F ratio is while cruising?

and when you say you advanced the timing, i'm guessing you mean ignition?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by chainsaw &raquo;</TD></TR><TR><TD CLASS="quote">have you been able to check what your A/F ratio is while cruising?

and when you say you advanced the timing, i'm guessing you mean ignition?</TD></TR></TABLE>

a/f was ~14.5 cruising...

yes I meant ignition timing. Cams are still at 0,0 for this baseline tune.