OK im going to try to explain this the best i can. I have a 99 civic si, pretty much stock, besides a skunk 2 tb and a full exhaust. I bought this car a few weeks ago and it runs strong. I did notice that when driving at normal hwy speeds or any gear, I would get a Random/slight stutter or a cut out, for a split second. I have changed my spark plugs, new plugs new distributor, cap ,rotor and im still having this problem. If i step on it wot, it will not do it or if i let off the gas it wont. Ive check my fuel and im getting plenty of fuel to the rail. I had a map sensor code and a O2 sensor code and i replaced them as well. I'm still having this stutter. I am lost and cant figure this out. Can anyone else shed some light on this problem. Ive heard of checking the timing and the tps sensor, but i have no codes (which tps should throw one correct?)and i just don't think its my timing it idles fine and runs strong just have a random stutter. Cold start has a little rough idle for about a few seconds in till i rev it up, then its back to a smooth idle . car idles at 1100 rpm. PLEASE HELP !!!!

 

I would try a new TPS. Ive had similar problem

 

so your tps gave you the same problem without a cel?

 

anyone else?

 

im having a similar problem, except my car sputters during partial and no throttle. im trying a new fuel pump tomorrow, will let you know if it helps at all.

 

If you run your car at the same speed (highway driving) a lot with the throttle in the exact same place it burns a small spot in your TPS, called a glitch. Get a lab scope, hook it up to the signal wire and with KOEO slowly open the throttle by hand, the voltage should rise slowly in relation to the throttle blade, if it dives down then comes back up, you have a glitch and need a new TPS. Glitches don't throw MILs. This sounds like your problem since it's during highway driving in any gear.

Note: You need to back probe the signal wire, do not unplug the sensor during the test, if you need more details on how to perform it PM me I can give you a step by step process.

 

Thanks! just pmed you! I will definitley post up once i find problem!

 

Same here on 00 Si... Mine is especially bad during partial throttle.

 

walbro 255 helped me out. engine is a b16a2. car is ready to rice it up this weekend, unfortunately i work all weekend

 

It's not called a glitch, it's called a dead spot.

 

Mechanics will refer to it as both, with reguards to speaking about the physical potentiometer inside the TPS, yes it would be a dead spot, on the lab scope screen, it is typically refered to as a glitch in the voltage over time line.

 

lol. We have the same picture. And sorry I've just never heard that term used for a dead spot on a TPS.

 

Yeah, I've been trying to find a new one today, getting tired of the old Honda H hanging around under my name.

Any luck with the diagnosis and/or fix OP?

 

^hah. yea, my daily grinder (D16Y7) is experiencing thus problem as well! dips about 500rpm for 1-2sec wen i hold it at about 2k or so, idles fine at 600. attempting to smog it and tried everything (full ignition, fuel filter, crc fuel clean w/91 oct, diff cat and sensor, throttle cleansing, retard timing). next step was to check the iacv and tps. q:would a bad tps throw a smog test off w/o a cel? it wont pass due to high carbon/hc (running rich)...

 

The reason the car will stutter with a glitching TPS is that the ECU "sees" the throttle blade being closed for some reason and cuts off the injectors, hence causing a little loss in power momentarily until it "sees" the voltage rising normally again. So a rich problem doesn't exactly make sense in that scenario since it's cutting fuel, it sounds like you may have some other issues going on in addition to a possible TPS issue.

 

See the attachment for an example of what a glitch looks like on a lab scope, although ignore the text next to the glitch, that's not exactly a correct statement by whoever did this picture.

 

some good info here, helped me out big time

 

good stuff one more thing i know if i ever have this problem...

 

Glad some folks got some help out of what I wrote, if folks are interested, I could do some write ups on how to test most of the sensors in your car for faults? PM me if you'd be interested in seeing something like this.

 

Well finally replaced my tps sensor and im still having the stutter,hesitation ,misfire, what ever you want to call it. I ve replaced my whole throttlebody with new tps and map sensor, distributor,spark plugs wires and o2 sensor. Im just lost on this problem. I did play arond with the distributor and when advance it will stutter/ misfire and back fir like crazy. with it the other way it will run some what better but still has a slight hesitatation but it feels weak and slow. Ive taken my d16 cap and rotor off and it mounted right up to my b16. Could this be a problem? i mean it fits and cranks but still have a stutter. It did the same with the b16 too.

 

still having problem! anyone!

 

Valve lashes are set too high that causes misfires, adjust that bro theres a diy on here about that. Reset them to factory settings and i promise it wont misfire i was just in the same shoes as you.I replaced everything you did also and my car was back firing crazy too! but after that adjustment nope!

 

so your saying i need to adjust the valves?

 

That's what he's saying. Give it a try.

 

Update??