99' LX470 occasional rough idle/misfire (1 Viewer)

[BillysIdol]

Hi,
Ive had my new-to-me LX470 for about a week now, and the other day I started it up and with in a minute or two the idle was really low, rough and the truck was misfiring. No CEL. After about ten minutes, it starts idling normal. Right around 550/600 RPMs smooth as can be. When it runs rough, it feels real snotty until it gets above 2000 RPMs, and then seems to feel OK.

I am going to do coils and plugs, but I am skeptical that it will resolve the issue. Has anyone experienced an issue like this?

 

[Ninja Cruiser100]

Water in gas? Fill tank up and try to dilute.

 

[trdcorolla]

Was the timing belt replaced recently? That happened to me after I had my timing belt replaced. It took a week or two for the check engine light to turn on. I was getting random misfires in techstream. I replaced all 8 coils with Denso and the problem was still there. It ended up being when the timing belt was installed, it moved so it was off a tooth, so my timing was off. Had the timing belt removed and reinstalled and my problem went away.

 

[BillysIdol]

Was the timing belt replaced recently? That happened to me after I had my timing belt replaced. It took a week or two for the check engine light to turn on. I was getting random misfires in techstream. I replaced all 8 coils with Denso and the problem was still there. It ended up being when the timing belt was installed, it moved so it was off a tooth, so my timing was off. Had the timing belt removed and reinstalled and my problem went away.

The timing belt was replaced by the original owner 30,000 miles ago. First few days of driving it and I didnt have the issue. It only happens when it is cold, and after about ten minutes it starts running perfectly. The motor is quiet and smooth, so I doubt there is any issue with timing. It seems more like electrical/ignition related.

 

[roma042987]

sounds like a bad coil

 

[MongooseGA]

sounds like a bad coil

This. Start unplugging them and see how the engine runs with each. If it's worse, that's not your problem. If it's the same, there ya go.

I had a similar issue in my SC400. Battled for weeks with everything I could think of until a friend finally loaned me a coil and bam, back to butter.

 

[trdcorolla]

I kept all my old coils as spares. If you were close by, I would glady give you one or two of them for free.

 

[2001LC]

I find coils tend to do worst when hot as resistance goes up from heat. If you have access to tech stream you can watch for misfire at start-up. I found a coil misfire once while looking at transmission fluid temp. As I put into gear with foot on brake to load transmission (heat ATF fluid), misfire accrued which readout happen to be on same page in tech stream.

Have you gone thought all vacuum lines, checked air filter and general tune up yet.

 

[BillysIdol]

Well I replaced all the coils and when doing so found a small crack on a vacuum line bunge on the air box. JB weld and the new coils seems to have cleared it up. Now on to suspension issues

 

[2001LC]

Well I replaced all the coils and when doing so found a small crack on a vacuum line bunge on the air box. JB weld and the new coils seems to have cleared it up. Now on to suspension issues

Can I ask which coils, where bought and how much you paid?

I'm always on the hunt from real Denso coils deals

 

[BillysIdol]

Can I ask which coils, where bought and how much you paid?

I'm always on the hunt from real Denso coils deals

I got the coils from a local shop. They aren’t Denso coils but the brand standard. They look good...see how long they last. If I remember correctly I got all 8 and spark plugs for under $300

 

[Poncherelli]

Can I ask which coils, where bought and how much you paid?

I'm always on the hunt from real Denso coils deals

I just scooped some denso coils off amazon, and if you scroll down you can see the “returned” items they resell for about 30% discount. Last denson cool cost me $35.

 

[2001LC]

I got the coils from a local shop. They aren’t Denso coils but the brand standard. They look good...see how long they last. If I remember correctly I got all 8 and spark plugs for under $300

That is supper cheap.

I just scooped some denso coils off amazon, and if you scroll down you can see the “returned” items they resell for about 30% discount. Last Denso cool cost me $35.

Last set I bought off ebay for $35 were counterfeit Denso, I sent them back.

Best deal I know of anyone getting for Denso coils was $45 ea. They had some coupon/discount and cough a special.

 

[morganism]

Sounds like you just drove it enough to reset the "readiness drive monitor". There is a link in the 80 FAQ on the tech bulletin, and how to set it, after you have disconnected the battery.

 

[Poncherelli]

That is supper cheap.
Last set I bought off ebay for $35 were counterfeit Denso, I sent them back.

Best deal I know of anyone getting for Denso coils was $45 ea. They had some coupon/discount and cough a special.

Box and product looked legit to me. Best I could tell it was a return to amazon but never used. The plastic interior bag was opened but everything was unused.