Weird idle problem when car is warm, help?

[dizzle209]

Hello everyone, I'm a new LS owner. I just got a 95 with 180k miles on it. Not sure what's been replaced. All the fluids look new though.

When I drove it for the first two days, it ran perfect. But after a while I've been noticing that when the car runs cold, it idles fine and no bogging/hesitation at all. After it warms up (usually after I drive somewhere then start it up again to drive somewhere else) the idle drops really low and it shakes a little in neutral/idle. When you shift it kind of bogs until you reach about 2k RPM. Same thing in about every gear. I feel a loss of power until I hit about 3k RPM then it lurches forward normally.

Now the weird thing is, I drove it a lot yesterday and it didn't act up at all. But I did notice that my temperature gauge was on cold so I think my thermostat is probably stuck open. Do you guys think that this is what is causing it?

My only fear is that if I fix my thermostat, the idle problems will come back. I've already replaced the spark plugs with NGK Iridiums. Next thing I was thinking of was cap, rotor, fuel filter, and wires. I can also replace the primary O2 sensor if needed.

 

[choyoyoing]

Hello everyone, I'm a new LS owner. I just got a 95 with 180k miles on it. Not sure what's been replaced. All the fluids look new though.

When I drove it for the first two days, it ran perfect. But after a while I've been noticing that when the car runs cold, it idles fine and no bogging/hesitation at all. After it warms up (usually after I drive somewhere then start it up again to drive somewhere else) the idle drops really low and it shakes a little in neutral/idle. When you shift it kind of bogs until you reach about 2k RPM. Same thing in about every gear. I feel a loss of power until I hit about 3k RPM then it lurches forward normally.

Now the weird thing is, I drove it a lot yesterday and it didn't act up at all. But I did notice that my temperature gauge was on cold so I think my thermostat is probably stuck open. Do you guys think that this is what is causing it?

My only fear is that if I fix my thermostat, the idle problems will come back. I've already replaced the spark plugs with NGK Iridiums. Next thing I was thinking of was cap, rotor, fuel filter, and wires. I can also replace the primary O2 sensor if needed.

It may need a full tune. Might be the spark plugs. I don't think it's the timing because it ran fine for 2 days...and now all of a sudden this is happening. Probably a terrible guess, but whenever I buy a used car I usually always have a full tune done. Weird how it started doing this after a couple days....have gone racing in those last couple days...? ? ha-ha. You might have thrown something off.

 

[dizzle209]

Nah, I babied it pretty much. Never redlined it or anything yet. I already did spark plugs, but I think a full tune up wouldn't be a bad idea. I'll have to wait until I get paid this Friday though. Yeah that's the weird part, it started acted up after a few days and now it went away when I found out about my thermostat.

My first guess was that it was ignition related since the car idled pretty bad after it got warm, and also when I had the AC on, it would surge too. Like jump from 500 to 900 RPMS. Common thing would be to replace spark plug wires since it happened on my friends Civic too.

 

[ameverden]

Nah, I babied it pretty much. Never redlined it or anything yet. I already did spark plugs, but I think a full tune up wouldn't be a bad idea. I'll have to wait until I get paid this Friday though. Yeah that's the weird part, it started acted up after a few days and now it went away when I found out about my thermostat.

My first guess was that it was ignition related since the car idled pretty bad after it got warm, and also when I had the AC on, it would surge too. Like jump from 500 to 900 RPMS. Common thing would be to replace spark plug wires since it happened on my friends Civic too.

Dizzle...Did you ever figure this out? I have the same issue and am working my way through each system (air, fuel and spark) but can't find anything bad. Everything I tested on the ignition looks good, the IACV was real dirty but after cleaning it, the TB, etc. problem is still there. I ordered a fuel gauge to test pressure of the pump and regulator operation (but this doesn't make sense since it starts fine and runs great cold). Whatever is causing it has to be connected to the coolant temp. I have no codes, still get good gas mileage, but this hesitation when I accelerate is getting real annoying. I'm hoping you figured it out!

 

[ameverden]

Any ideas out there?

I have been reading a ton of posts with similiar symptoms to this one but have yet to see where anyone followed up with something conclusive. I have completed a full tune up (including timing check) and replaced my IACV (with brand new one) but still have the hesistation at lower rpms when the engine is warm. Does anyone have any ideas? I'm leaning towards the O2 sensors but it doesn't make sense with no CELs and great performance above 3K rpm.

 

[Afireinside]

I had this happen once before and the problem was that one of the spark plug wires was arcing to metal down inside the valve cover.
The wire set was only about a year old and a nice 8mm set. I just replaced the wires and it's still good.
The problem is if your not really careful in removeing the wires when you change the plugs they can develope small cracks that typically affect idle since at higher rpms it's kinda forced to go to the plug.

Good luck

 

[cizkaro]

I had this happen once before and the problem was that one of the spark plug wires was arcing to metal down inside the valve cover.
The wire set was only about a year old and a nice 8mm set. I just replaced the wires and it's still good.
The problem is if your not really careful in removeing the wires when you change the plugs they can develope small cracks that typically affect idle since at higher rpms it's kinda forced to go to the plug.

Good luck

I oddly have been having this same problem and been unable to figure it out. I will do a closer inspection of my plug wires thanks for the info fire.

 

[The Panch]

Im having this same issue on one of my civics. my guess Was CLOGGED CAT. but still havent checked