Hi all,

I've made a bit of an effort to look around, and maybe I can't think how to condense the issue I'm having to just a few keywords that might get a result, but I've not had much luck thus far.

Car is a 1993 Honda Accord, ~250k miles on the car, ~150k on the engine.

Pertinent info: (Sorry if this is overkill..)

-I just replaced a bum starter.
-I'm 99% sure my heater core is blocked up/broken/not working, I haven't gotten to it yet.
-There's some general electrical issues I'm slowly working through.
-Shorting out the plug to get the check engine code just causes to the light to stay on, no codes or any such luck. I'm told since it doesn't start with the light on, it won't throw a code either. (*shrug*) Edit: Throws a "43" ...

And the problem:

So I start up the car, check engine light is off (you'll see why I mention it), and get on the highway. Accelerating feels normal, but as soon as I let off the gas just to maintain speed (rather than, y'know, go faster) the car shakes like the gas flow is in spikes... I'd say idling very rough if it was idling. Fairly worrisome kind of shaking. The problem goes away if I accelerate, comes back as soon as I back off.

A ways down the road, say 5-10 minutes, the problem clears up in kind of "it's doing it.... and now it's not" and as soon as it quits, the engine light comes on. There's no problems until I park it and the car cools off. Rinse and repeat.

Any pointers as to what the deal here is would be greatly appreciated.

P.S. I'm going to change the fuel filter and spark plugs just to see if that helps anything later today.

 

try cleaning the IACV,throttle body and EGR valve. these are quick and easy fixes that won't cost you anything but a bottle of carb cleaner if you don't already have one. there are a bunch of DIY videos on youtube.i would also use some seafoam

 

Fuel filter and spark plugs didn't help any. I did clean the throttle body and IACV, haven't messed with the EGR.

I did get the check engine light to throw a "43" so.... replace O2 sensor? Does that make sense for what the car is doing?

 

could be since the primary oxygen sensor determines the air fuel ratio. most oxygen sensor are only good for 60,000 miles. only use DENSO or NTK oxygen sensors.

 

Just to follow up -- I replaced the o2 sensor and my problem cleared up. Thanks!