Finally got the car running. It idles great, no more stalls when stopping. Hot starts great, sold starts great. Went for a drive and now have a new problem. When accelerating at speed (like 60 - 65 mph), not stomping the pedal but pushing firmly, I get a big-time stumble or hesitation.

Basically stock Nikki, emissions crap removed. Didn't check fuel filter yet, but it was replaced a few hundred miles ago.

Not sure where to start looking for problems. I have zero experience playing with the secondary system, so I don't know if that's where I need to look. Is there any other driveability testing I need to do? I didn't try any full-on pedal stomping checks because I also have a squealing belt and the noise is making me crazy. I'll fix that and move on to the stumbling.

 

replace the belt, check for good accelerator pump operations. Start there, and I am sure other people can give you more suggestions.

 

accelerator pump thats where my $$ is

 

AP seems a reasonable suspect. Problem is, I can't get it to happen again. It was the first few drives after I got it put back together and on the road. I'll keep waiting for it to happen again.

 

Nah, the AP pump shot is gone by then if your foot is down on the pedal. Possible but not likely. Maybe you had a clogged jet or bleed. Now that its better, maybe it cleared itself. Keep an eye on it.

 

But it wasn't a pedal stomp. Didn't floor it, just pushed down and got the stumbles. OTOH, it's not happened again. Maybe it was telling me it needs to be driven more often. Hurt me.

 

Mine 85gs 12A happened exactly the same thing. Its been like this for a month now still couldn't figure out the problem.
update on stumbling and loss power at high speed. I noticed the problem occurred when the exhaust sensor cord got ripped off and i put in back in where it belong and clamp it down. Last night i decided to pull the sensor cord from the exhaust, I felt the stumble for a few second at 3k rpm 5th gear. Then i kept pedal the gas and it just took off. I drove for 1/2 hr on 5th gear @4k rpm but couldn't go any faster. The problem seems to be with the exhaust???
Where is the acceleration pump located? What defect do i look at? Please help my 1 and only beloved daily driver.

 

I always had a stumble when i had my stock nikki on the car. It was only when i would romp it though. It was extemely annoying. It started right before i got my sterling carb so i just tried to ignore it till then. But now my car runs great with the sterling carb

 

So the problem is the carb? I just need to get it normal driving while i'm saving up for a sterling carb.

 

*my* stumble problem was the carb.

 

Stumble at high rpms indicate fuel delivery problem. It can be in the carb, but it can be fuel filter, fuel pump, kinked fuel line, clogged fuel line...

 

I hated to do anything with fuel or electrical, i don't know anything about it, guess i have no choice. When i pulled the exhaust sensor cord from the pipe, i was able to gain another 1k rpm @5th gear. I check with a local shop that knows alot about rotary, he said he can diagnostic the problem for 1-2 hrs for $40. Is that a good price?

 

I found my prob through the process of elimination. first the filter...nope. Then the pump (replaced the stock with a 16 psi pump).......nope. Then the carb..........YUP!

 

sure, as long as his diagnosis is spot-on.