Low RPM miss...

[buffy]

Bought an 04 couple weeks ago. It had a full yosh exhaust, but no power commander. I installed a TRE first, some said it might help. I then purchased a PCIII USB, loaded map from dynojet for the full yosh exhaust. Still no help with the low RPM miss. It seems toline out about 2500 rpm and run like a stripped ape after 2500 rpm.
I did look at the map and it does nothing, has zero's in the lower rpm's. I put in 15% more fuel on anything under 2500 RPM's. It runs a whole lot better however, I think I'm just putting a bandaid on an original problem.
I've sync the throttle bodies,checked the clamps on the throttle bodies.
Could it be a bad sensor?theidle is all over the place, erratic as can be.
Thanks, buffy

 

[GIXERHP]

Is the air box modified?

 

[buffy]

Is the air box modified?

Nope, stock air box.

 

[MC MUSTANG]

If the idle was that eratic, how hard was the sync?

 

[rubber2burn]

Know you said it had a Full exhaust but when they put it on did they remove the Pair valve? If not that might be an issue.

 

[Mr Bogus]

you need some more information (exhaust gas analyzer would be most helpful)

if you have a partially plugged injector, this can create a lot of issues at low duty cycle. it would still act up at higher rpm but less noticeable.. You could try some "in the tank" injector cleaner

Sparkplugs: probably the cheapest "shot in the dark" and a possible issue, look for any black electrodes when you pull them.. At least you might find the offending cylinder,,

Vacuum Leak.. another good possible problem (hoses, boots etc, a bit of carb clean will find it, make the motor miss, a light spray around fittings, hoses etc, if there is a leak, you will know it...)

PAIR valve should not cause any problems unless the vacuum line is bad or the valve itself is ruptured.. (can cause a vacuum leak) block off plates etc will not have any effect on the problem..

 

[mikejmarine]

you need some more information  (exhaust gas analyzer would be most helpful)

if you have a partially plugged injector, this can create a lot of issues at low duty cycle. it would still act up at higher rpm but less noticeable..  You could try some "in the tank" injector cleaner

+1 I'm having the same problem at the moment, not to your extent. but never the less. I put Lucas fuel injector cleaner in the tank and there was a noticeable difference (after a few miles)

 

[buffy]

When I did the carb sync. I just matched them up as the mercury fluctuated up and down the scale.
Already checked the plugs they are not black, actually a light brown probably where it needs to be. I think it's a lean condition, since I put 20% more fuel in the map up to 2500 rpm, seems to have taken most of the miss out. However, just a bandaid until I find the real problem. I know johhny cheese does not like TRE's. I might take it when I get a chance and try that. I will also try the leak checker. Working in the hay right now and not much time to play with the bike.
Thanks guys, buffy

 

[Mr Bogus]

to find out if it is a plugged injector, you need to get at the individual stacks..

A short blast of carb clean down each stack will bring any lean cylinder online for a moment as it gets its proper A/F..

IF you find this works, you need to pull "all" the injectors and have them cleaned and matched or get an exchange set (someone here was saying they would do an exchange, perhaps GoldenChild?)