I've got an 89 Honda Accord DX, about 204000 miles, manual tranny. About 3 weeks ago i took it to a place to put on the scope machine to figure out why it wouldnt pass my local emissions testing (Nashville, TN). I got the car back running better then before, even after several part replacements and adjustments by my neighbor who is a certified mechanic. About 4-5 days ago i got in the car and down the street, when i got to the stop sign and hit the brakes to stop, the cars RPM's dropped from its usual 1200 to around 400-500. Of course it started running really rough at idle, as soon as i put it back into first and took off it was like performance had dropped and it continued to run this way at every stop i made or even when i just pressed the clutch and coasted. My neighbor suggested i check all my vacuum lines for leaks, tears, or even any missing. I did so and found nothing unusual. One thing to mention is that my water was low because of a leaking water line to the engine block coming from through the other side of the firewall. This water line sits just below the distributor. I'll be fixing that later tonight after the engine cools down. Does anyone have any idea what this could be? The only change i remember is using a lower grade gas, 87 rather then 89 but the car calls for 87 anyway, i only use the 89 once in a while for the better performance. Please help me...im out of ideas =<

 

Well i fixed the water leak and its still running rough...odd thing is it only starts doing it when i put it into a gear and go for a minute, then let up off the clutch...right after i let out the clutch it drops down to 400-500 sputtering and struggling to stay running. Also, it sometimes just goes back to normal...though only for a short period of time.

I did notice that my oil cap's seal is pretty messed up so i'll replace that tomorrow when auto shops open. Could it really be that simple though?

 

Make sure you bleed the cooling system using the bleeder on the t-stat. 89 DX should be a carb engine. So first off the idle sounds high (1200), normal is somewhere from 750-900. But I don't think that is the issue but it could be. Double check the vac lines (I've replaced #7 on the back side of carb on more than one carb 86-89) and base gasket for leaks. Also when idling look into the carb and make sure the float needle isn't leaking (drops of fuel instead of a fine spray). Might as well clean the heck out of it while you are there (Carb cleaner or Seafoam, both). Also if this is only happening after it gets warm that does bring the egr system into play as well. Sorry I don't have one single answer, just additional ideas to test/inspect.
Saw your post on another forum. I'll answer only once on here.

 

Thank you poorman212, I did in fact bleed the coolant system when i fixed the leak last night. Number 7 was in fact off, B was also disconnected. I also found that a couple other vacuum lines were bypassed or capped off (looks like im not going back to the same shop <_<).

I uncapped and reconnected the lines, the lines that were capped were 25, that goes to this black thing (honestly dont know what the thing is, please tell me if you do) and 17 which goes to the air cleaner.

After reconnecting said lines, the engine seems to be running like it was just after i got it back from the shop. (dont get me wrong, it was running perfectly after it came back from them) Though it still seems to be sputtering a little...i could take a video of it from my phone which takes pretty good quality if it would help figure out what still needs to be done...This way you could see and hear the engine running for yourself.

 

Also...there seems to be a vacuum line missing from the back left side of the air cleaner from the front of the car. Theres also a cap on a metal vacuum line just below it, if i take that cap off while the engine is running, the engine jerks and sputters like its having a seizure. I cant for the life of me figure out what it connects to.

 

A pic might help for the missing one one the air cleaner, the 89 LX auto is home today so I can use that as a reference. Are the little plastic numbers left on the metal tubing where the cap is?
Edit: "the other end of "#17 that goes to the "black thing" on the t-stat housing. That thing is a "Ported Vac Switch". Means that at a certain temp the switch either opens or closes to allow or stop vac from going somewhere.

I'll go back out and look for #25, sorry for mis reading.

 

#25 goes to a black thing on the Dist. That would be the vac advance, controls the change in timing for the ign.

What parts were replaced and what adjustments were made? What part of the "test" did the car fail?

 

I can do that, give me about 6 minutes after this post and i'll get the picture of it.

Its 25 and 2 that connect to the black thing on the distributor, if thats what you meant..

Is it possible that my switch is malfunctioning?

 

ignore the red wire, its for the fog lights, i just havent rerouted it yet. (previous owner installed them)

 

Im not sure what part of the "test" the car failed. It kept failing emissions testing for HC, they somehow got it from over 500 to 32. My local limit is 220.

I know they didnt replace any parts, they just told me they set everything to factory specs.