Sorry about the title so let me explain the symptoms. Bought the car last week and it was running fine. While I was driving the other day it started to feel funny. Like it was miss firing on a cylinder. Ir would vibrate (not bad) when you gave it gas and began Idling rough. I am planning on changing out the plugs and wires this week. The real concern is that on another occasion I was driving home with the same symptoms and the car shut off. It would crank but I had to keep revving it to keep it going so I could limp home. Wondering if it's MAF related.

Any thoughts or suggestions.

TIA

 

Did you try unplugging the maf and see if there is any difference?

 

Yes. It will not crank with the maf unplugged. While running when I unplug the maf it seems to struggle to maintain idle. Does not idle as well with the maf unplugged.

 

Bump! Bump!

 

Read this article if not already and report back your findings.

https://www.clublexus.com/forums/per...on-issues.html

 

Thanks I have read through this article several times learning as I go. I need to pick up a new mulitmeter with insulation piercing leads then I will give it a go.

Thanks alot. I'll let you know where this leads me.

 

Your throttle linkage bolt might need tightening, fat chance but it's worth a check. The throttle linkage bolt is under the plastic cover above the TPS and throttle body. There will be 3 bolts, 11 mm I think, if the bolt is at all loose, tighten it up. After that, I would check stuff like TPS, IACV, and so on. ^BTW, in this case, your SC400 doesn't have a MAF, it's an AFM, same thing, except that the AFM uses karmen vortex air meters to detect air flow and these parts are very delicate. Don't clean them with MAF cleaner. It will ruin them. Good luck brother!

 

SC400slide thanks for the suggestions. Interesting about the AFM as compared to a MAF. I was going to clean it but will not now. Can it be cleaned?

Another question is about codes. I don't have a CEL on but if I hook the car up to a code reader could I possibly pick up some codes?

 

No, you can only pull codes with a CEL illuminating. The way you would have to clean the AFM is with air. Strong air, like an air hose. I think that's the only way it can be cleaned...
GL

 

I have a 1993 Lexus SC400. I have a diagnostic tool and it when I plug it in it says there no response. This is what the car is doing: The car is hard to start, when it starts it wants to die out, when you give it the throttle the car just goes blog. It almost sounds like it is misfiring. The engine light is on. The RPMS go up and down. When the car sits for awhile it seems to run ok until it hits a certain tempeture. The diagnostic tool where it plugs in I took a test light and and I have power to it and the test light lights up. Can you help me figure this out?

 

Search on this site - there all you need to pull codes is a paperclip... very simple...

once you do that, report back with the codes...

 

Hey johnsikors, you can make your own thread instead of "jacking" a thread. I think that's what we call that...
Did you try and rule out everything on this thread?