Well look at that; I'm also showing a P1491 and a P1399 (1491 is thrown; 1399 is pending). Before reading sigmaforce's posts I was thinking the 1399 (ignition system or misfire) was the real problem and that I'd just go back and regap the new plugs to .040 as specified by the owner's manual instead of the .044 I read online. However, sounds like EGR valve might actually be the problem instead.

So, where to from here? Can I clean out the EGR, or does it need replaced? Or should I start by regapping the plugs and see how things go?

Muchas gracias

EDIT: I should've mentioned that I've also got a ULEV... I'm in PA, but we bought it used, and the valve cover says ULEV on it.

 

P1491 = EGR valve insufficient lift

I suspect the EGR is the same between the ULEV & non-ULEV engines. Maybe just the programming for when it opens.

EGR is not supposed to be open at idle, so maybe it's sticking open when you slow down (ie. sticking for a few seconds before it actually closes). That could probably cause the misfire.

Older Accords (before 1997) have more restrictive EGR ports in the intake manifold, & they tend to get plugged up with crud. Not sure how that compares...? But I guess that should result in P0401 (EGR insufficient flow).

Probably can't hurt to take off the EGR valve & see if it's full of baked-on carbon crud?? Check the passageway in the manifold too.

 

After doing some more reading, seems like most Accords end up with gunked up/blocked EGR valve ports and runner at one point or another, so I'm thinking this is where I'll start.

From what I understand it can get gunked up in a couple of places: where the EGR bolts to the engine (both ports), as well as where the runner from the EGR valve opens up into the intake manifold, where the upper and lower halves of the IM bolt together. Thing is, I'm not sure exactly how to get everything apart so I can get at it to clean it up. The 5 bolts holding the two halves of the IM together will be easy, but there's all kinds of cables and wires and coolant lines and vacuum hoses back there, not to mention the fuel rail and injectors in the way, and I don't want to go tearing it all apart without knowing the proper procedure. For instance, how important is it to replace the gasket between the two halves of the IM? How about the EGR valve gasket? I've look all over for a DIY, but the only thing I can find is either for 5th-gen Accords, or 6th Gen V6's, not 4-cylinders. Anybody have a link, or experience to lend?

 

old thread but hoping it was resolved?? My 99 honda is having the exact same issues....

 

I'm up in Portland Oregon,
. I bought my 99" Accord last year with a 118000 miles on it From the original owner with all the Maintenance receipts and papers. It was well maintained from an old couple. Im About to hit a 130000 miles and it started doing The same thing, it's good to see I'm not the only one and I appreciate all your input. I'll keep yall posted. You guys have any answers I'd really appreciate the info Thank you