Intermitant Rough engine

[pat8635]

I just acquired a 1988 Accord LX 4 dr. 2.0L MT that has been my dad's rarely used car for many years.

That car was in VA and had trouble passing the state emissions test...so his mechanic got it through for him....

For the last year when I was home the car has had a rough idle and has not run well. He gave it to me a few weeks ago and I drove it back to Texas where I currently live.

During the 1700 mile drive I put a few cans of BG44k or Techron (very similar products) gas additive that worked to fix a Mazda 929 check engine light for me many times. Car is running better and got 37mpg on the trip and is getting over 30 with AC on town here. Something isn't too wrong..or so it would seem to me. But an engine not running smoothly is hard for me!

Car is always smooth on deceleration. I have shifted down and gotten RPM up over 4K. Always perfect.

I have, since getting home, replaced-- Ignition wires, plugs, dist cap, rotor, fuel filter (front need to get under for rear) & air filter. I also have a new PVC valve, but can't seem to find anything that looks like what I bought on my car...Humm...

The first plug had what looked like a piece of carbon the size of a hole from a paper hole punch in the gap area. Not enough to ground out the plug, engine ran too well for that. After a few hundred miles the new plug is very clean and looks good.

Timing and idle are fine. Idle was at 1K now is at 750/800 after above work.

Engine gets rough either at constant speed or acceleration isn't 100% at random intervals. It seems worse if I start the car after it sits for a awhile and gets better, but that is not a constant. Before I started this my service writer for my newer accord looked at the vacuum system and said that he didn't believe it was the vacuum system, would be more constant and hoses looked like they had been replace in the last few years...so I am stuck...

Any ideas? I added some engine restore to the last oil change. Behind the car when it does this it sounds like a cough or a hiccup.

[sunderland]

I bought my carbed 3G about 8 months ago. Did most of the things you have done to get it to idle right. Then found that all my motor mounts were bad. Replaced them and it runs smooth as silk.

[pat8635]

I bought my carbed 3G about 8 months ago. Did most of the things you have done to get it to idle right. Then found that all my motor mounts were bad. Replaced them and it runs smooth as silk.

How would one check the motor mounts. On my to do list is to check the Transmition...The clutch every once in a while doesn't seem to have the free play that it should have before engaging....

[sunderland]

First, do a search for "motor mounts" on this site. That's how I learned about the relationship between motor mounts and a smooth running 3G.

The best way to tell if they're bad is to remove them, because if you pressure wash your engine compartment, they might look good on the outside when, in fact, they are deteriorated and broken. You could try to pry with a large screw driver or use a mirror on a long extension. The front one, in front of the exhuast manifold, is filled with oil. If it's bad, the oil has leaked out.

I went with the overall consensus on this site and ordered Honda mounts from Majestic Honda. Replacing them was not too difficult.

http://www.hondaautomotiveparts.com/...5=ENGINE+MOUNT

I think you would need 2, 3, & 8.

[pat8635]

I did a search...many other things came up. To save time. I wend to Honda where a friend of mines is the service manager. He put it up and said that the motor mounts looked good...The car had been in an accident years ago and they were all replaced then.

Seems like a bunch of work. I would expect a more consistent problem if the mounts were the case. When the engine has a cold start is runs perfectly. I live in a very warm Texas so that is short lived...

[pat8635]

I did a search...many other things came up. To save time. I wend to Honda where a friend of mines is the service manager. He put it up and said that the motor mounts looked good...The car had been in an accident years ago and they were all replaced then.

Seems like a bunch of work. I would expect a more consistent problem if the mounts were the case. When the engine has a cold start is runs perfectly. I live in a very warm Texas so that is short lived...

[A20A1]

https://www.3geez.com/forum/showthread.php?t=69

[pat8635]

wow...that is easy to get to...can you get to it from below easier????

[A20A1]

nope, it has to be pulled from the top. First remove the air box... careful how you pull off the vacuum lines that are connected under the air box, you don't need to create any more problems with a vacuum leak.

[pat8635]

Tempted to replace all the vacuum lines just because...just looks like a real big headache.....but with the fact that it runs well under cold starts...makes me wonder if there is a vacuum issue, they look good....but you never know!