I've got a 99 auto CX hatch (D16Y7). It's my winter car, so it's been sitting for the pat 6 months or so. Basically if I apply the throttle very lightly, the car is really jerky - like the throttle gets flipped on then back off again every second. Anyone know a fix for this? Thanks.

 

when you start the car, or while driving? I notice my 99 ex does this if I try to hold the throttle in 1 specific spot while driving.

 

It's while driving. If I hold the throttle lightly in one specific spot, it does this. Like if I'm driving in a parking lot or in a place where I'll be driving slowly for a not so short distance but at low speeds. Not a huge problem, just really annoying.

 

You both can do a resistance check on the throttle position sensor. Make sure you see a smooth transition in resistance across the entire range.

Are all of your other tuneup items in order? I've had Civics in the past have funky misfiring issues and it was usually ignition components in poor condition. Has the ATF been serviced recently?

 

 

I've swapped my o2 sensor already so I don't think that's it. The only code I have is for an evap leak. This also doesn't happen all the time. It didn't start until I started driving the car again about a month ago, and I wasn't able to make it happen on my drive home today. I'm very certain it's not a misfire as it's not sputtering or backfiring when it happens, it's literally a very even pattern, maybe half a second with power then half a second without, and back and forth until I let my foot off the pedal or give it more throttle.

Chances are I'm not going to do anything about it unless it's a sign of impending doom as this is just my winter beater, but I do appreciate the suggestions.

 

OP, does your issue occur at all times--warm or cold, or is there a specific rhyme or reason to it?

A failing TPS can break up specific throttle positions. Fuel trims based on the oxygen sensor outputs don't usually come into play until the car is warmed up when it enters closed loop operation.

You still have not mentioned any maintenance history. What's going on in that regard? What have you replaced recently?

The evap system leak may also spell issues. What code(s) is your car throwing off?

 

Well I'm glad you asked what the specific code was because it is different from the last time I checked. It's P0505, which indicates idle air control system issue. The evap code is no longer there but I suppose it's only a matter of time before it comes back too.

 

 

I'll take a look at the IACV this weekend. I have no idea about air in my cooling system, though I did have trouble with my car overheating last summer (the radiator motor was seized). How would I go about flushing any air out? I suppose I can just google it.

 

 

I never removed any coolant hoses, I just had to replace the radiator fan motor. That being said, the radiator cap did break, could that have caused it?

 

Actually on second thought, I probably had to drain the coolant and remove a radiator hose to get the fan off... I don't remember, it's been well over a year now since I did that haha. Anyway, I'll do a flush this weekend and see if there is much sir in the system. Thanks for the suggestions!

 

As for my issue, I haven't tried to duplicate the issue when the engine is cold, I will try that. I have no codes.
Maintenance;
new IACV
new plugs, wires, cap and rotor
new valve cover gasket (was leaking into spark plugs)
new fuel pump and filter
bleed the coolant system for 45+ min
I need to get some tranny juice and do an exchange. As well as check the TPS it seems.

Edit, its possible that after I swapped the fuel pump / filter it was better for a day or 2, although not 100% sure about that.

 

 

I do not know if this is the case, but I did notice that my 96' civic would be quite jerky at low speeds, almost like I did not know how to drive a manual (mine is 5-speed), but it went away once I used 89 octane gas. Maybe that is not what was causing it, but if the octane is too low, it would cause pre-detonation which I believe makes logical sense as too why my car was jerky under small load. The car would also almost stall at stop lights because the idle would be around 700-750 then drop to about 200-300 RPM. Ever since I used the 89 octane gas, this issue has gone away. This was recent, I will let you know if my problem persists.