When I first start the engine, rpm is close to 1500. Then I drive a little bit, it comes back to 700. It also has a little misfiring when idling. On highway, engine is strong and i dont feel any misfiring anymore; I have 2950 rpm at the speed of 75mph (7mgte and r154) I don't think it's normal like this. Any suggestions? Thanks!
Idling problems
- Thread starter Volvospy
- Start date
I have similar issues, i haven't taken note of the starting RPM's and such but i'm very interested in what you find, i'll be sure to share any thing that improves my idle quality , i had similar issues once with a 4L motor in a maxda pickup, after replacing the idle air controler it fixed the problem, but i must confess i don't know nearly enough about our cars, Yet 
i have same problem but i replaced afm and it helped still have a little misfire at idle..thinking of replacing my spark plugs soon seen if that makes any difference.
Well im pretty sure that the misfire is still there, Its just that the engine is cycling so fast that it doesn't depend on that stroke to keep going. When its slow and a little bit more dependent you notice it.
I had new plugs and wires. Misfire is still there. A friend of mine (old school guy) said it could be engine wiring harness. In my case I think my valve stem seals leaks oil and that would cause the same problem we have now. Sometimes I smell oil burn on highway. I checked valve cover gasket, it is not it. So the valve stem seals needs to be replaced first I guess.
Volvospy;1641477 said:
My seals were So burned this last rebuild when i flipped the head over some of them fell out :O haha and it was (only) burning a quart a week ^.^
Hahaha, thanks for your info dude. The damn seals need to be replaced fo sho, my car has 195k already
no codes my motor has just been rebuilt only 10k on it....i know a few other guys with supras there cars do the same thing...but i know others too and there's idles perfect...
Mine turned out to be caused by a small "U" shaped crack in the ceramic insulator on the spark plug, that only caused "break-up" under load. They replaced the bad plug, now it works better than stock! The plug that had the flaw was new. So check not only the gap but the insulator; :3d_frown: who knew? Van
one thing you can try to maybe isolate the problem is to loosen all of the plug wires at coil packs. Just have them "unclipped". Start the car and remove one at a time to see if the idle changes. Everytime you pull a wire off you should notice a signifcant change. if you don't, maybe you have isolated it down to that cylinder. (coil, plug, wire, injector, etc). Just something to try that is basic and easy. Also as the old school guy says, it could be harness related. Try touching/ moving every visiable wiring, espescially around the TPS..... to see if you can get it to change.