2000 leganza engine misses(FIXED), engine lopes on idle stil

[Ali]

Finally did work on a leganza with a blown head gasket while ago, but it's been running pretty poorly.

I've had the head machined, replaced blown gasket and any other gaskets, installed it with new head bolts, new fuel injector orings. It has a new thermostat as well.

When I start the car, it idles pretty rough but when you put in some revs it runs okay. After maybe ten minutes of driving in 60 mph (driving in the highway so a consistent rpm), the engine intermittently feels like it's skipping and when I slow down to an idle, it feels like it's about to die unless I rev it a little bit, and doesn't run as well afterwards.

I've been told it's maybe the ignition system or the battery. I didn't have the spark plugs replaced but they were relatively new. Then again they were bosch platinum +4s and I keep hearing bad things about them. I'll try and check the ignition system and maybe replace the spark plugs and spark plug wires anyways.

Any ideas?

EDIT:

MISSING FIXED: Replaced both plugs and wires, it was gone. It also doesn't feel like its about to die after 2k-3k rev driving for awhile then coming to a stop.

Still have the annoying engine loping on idle.

[iancowdery]

Don't know if this helps

This is a link to download the 'proper' workshop service manual (75mb)-

http://download150.mediafire.com/smbbwh ... nglish.pdf

[Trey05Woo]

I would start with the ignition system. Might have a half dead coil, or bad plug wires. The plat 4 are not necessarly a bad plug just not really for this specific application. Car will run fine with cheaper NGks or delcos

[Ali]

I've replaced my plugs and wires and driven it along on a nearby highway. The skips/misses are gone, I think, and so is the almost-dying idle after some work has been put on the engine. Normal idle is still pretty terrible, though. It feels like its loping, and when I let go of the brakes while in drive, it moves forward as if it were loping as well. I'm going to try to take a look at the IAC and the EGR valve maybe, but those are the only ideas I got.

Thanks, by the way!

edit @lancowdery

Thanks, but I already had the manual. Wouldn't have been able to do head gasket without it.

[Ali]

I've ordered the ignition coil before buying plugs and wires and it just came in, so I got it replaced. Checked out my O2 sensor (before cat), TPS and IAC. The O2 sensor and TPS didn't seem to work correctly, so I got those replaced as well. Nothing changed.

I'm going to try to look for a vacuum leak on the weekend. Not sure how to look for one but I got a hand vacuum pump so I'm going to check all the hoses that I can. Don't really know how to check EGR other than buying a new one and try it out to see if it's any better, but the EGR doesn't matter for vacuum in this car because it's electronically controlled, right?

[Puddle31]

maybe a stupid question but if the engine misses have you changed the fuel filter lately? maybe you got some bad gas?

[Ali]

It doesn't miss any longer, it just lopes annoyingly on idle. I've had the fuel filter changed out anyways too, so the missing problem was the plugs and/or wires.

[MMamdouh]

did you try cleaning your TB and idle controller

MMamdouh

[Ali]

Cleaned the IAC when I checked it and the throttle body after I was putting everything back together from the new head gasket.

[Trackerrrr]

Check your cam timing. I replaced the belt on my 1999 Leganza and had one cam one tooth off, loped at idle but otherwise ran fine. Reset the timing belt and all was well.