Does your car feel like there is something holding it back while cruising or accelerating? If so, do you think this problem could be due to the old brake lines? This was the problem for my car (SC400 almost 190k miles). I had the car since 125k miles and had such a hard time driving it ever since the 1st winter. Even worse than my first car, an '88 Firebird. I couldn't figure out why it was having such a hard time accelerating even in light snow. Just last winter my pass. front brake caliper stayed clamped on the rotor every time it would get too cold. yet this summer when it was really really hot the car drove with a lot more power than when it was just a cool day. I decided to replace the pass. front brake line with a stainless steel line just recently and wow what a huge difference! I haven't had time to replace the other lines but the car accelerates so much more with so less effort. Hope these solutions help any or all of your problems.

 

Havent gotten the new ground kit to verify if it clears up my cars hesit., hope to get it soon. Did try a bottle of Lucas fuel injector cleaner, 3oz. per 10 gals. Helps, but still not gone.

 

old thread, but bumping to the top since i have the same problem.

hesitation at idle and acceleration, cel comes on at idle then turns off when accelerating, but comes back on when off the gas.

code 31 pulled.

 

My hesitation seems to have completely cleared up. Im sure all the repairs I did were for the greater good. I stopped buying no-name gas and started buying Marathon only, and its running like new. A CEL would surely warrant further investigation.

 

code was for "VAF circuit"

anyone?

 

I installed my Lextreme TC to fix the hesitation I had, it did nothing. HOWEVER, when i unplugged my AFM the car felt so much better - CEL is on along with the Trac Off light, but I'd rather drive my healthy car with lights on, than driving a handicapped on with no lights

the TC still stall at 2200 RPM - weird

 

disconnect your AFM (unplug it) and then check what happens. I had the same issue today -

Try it and let me know

 

My wife just picked up a used 1995 SC400 (53K miles!) that had a hesitation problem. This seemed to happen at very low RPM and at about 45 mph. When we were looking for cars, we drove another SC400 that had the same problem. I thought it was a generic problem.

It is just getting warmer here in Phoenix (93 degrees today) and the car started going beyond hesitation, it would actually stall when first starting up.

The fix was to unbolt the Mass Air Flow sensor (in the open on top, right next to the air filter. Remove three screws and unplug from the wire harness, I had it pulled out in about two minutes. My MAF was labeled "Fuji electric 22204-42011 FMZ3AYY2". It is not much to look at. I expected to see two wires that I needed to clean, but nothing was really visible. There was a tall center post (the MAF sensor) and a smaller post (temperature sensor). I cleaned the smaller post (especially the tip) with a Q tip and a bit of water.

The tall post had I hole in the very bottom that seemed to have a silver plate at the bottom. The hole did not seem dirty, but I blew into the hole to try to blast out any dust, and tried to clean it with a part of a Q tip (the hole is too small for a full Q tip), but I am not sure I actually accomplished anything. I did not seem to get dirt from the hole. There was another hole near the mounting surface that I also tried to get to, but was not very successful.

The main thing that I did was to clean the V like surface of this central post. In retrospect, I think the surface of this V is where the heating/cooling MAF function takes place. It had a fine dust covering. I think simply removing this dust with a damp clean rag may have solved my problem.

When I put it all back together, I added a few drops of some very expensive electronic cleaning solution to the cable plug, plugged it in, unplugged it again, added a few more drops, and plugged it in a second time.

I feel like I had really accomplished much. I was expecting to see a pair of wires that I needed to clean, but nothing was really visible. I admit my expectations were kind of low.

The hesitation is now completely gone! The previous problems at low idle and at roughly 45 mph of hesitation are all now gone! Also no more stalling during the heat of the day. I am not sure if this was due to might few minutes of cleaning or the use of the contact cleaner, but my wife is now one happy camper.

This fix is well worth the few minutes to try out.

- Dan

 

this was a really great thread and i cant even place a value on it. I havnt tried some of the stuff that were said in this thread but it gives me so much hope.

I like how it went through the years dating all the way back to 2004 up until now. I hope everyone in this thread had their hesitation issues resolved. Driving the SC400 can be a dream when its up and going but that hesitation can drive a man damn crazy lol

 

mine does the same thing except it throws a code 31. i think its something like insufficient air flow?

 

I've read all 7 pages on this thread and I'm starting my journey tomorrow, wish me luck since I'm going out of town on it next week, thanks for all the info guys.

 

My SC4 has the same hesitation and on top of doing a complete sea foam cleaning, I'll be cleaning the MAF and hopefully it will cease and desist.

 

Any chance that bad O2 sensors could cause the hesitation?

 

I believe I am experiencing the same symptoms. I just cleaned my MAF and readjusted my trac and TSP. I will be driving it for a bit and see what happens. I am getting some bucking when letting off the throttle at ANY speeds, not sorta a hesitation. Its similiar to some of the other reports on this thread.

 

Just completely did a intake Sea Foam spray cleaning, and and Sea Foamed the engine through all three areas as stated on the can and wow! what a difference. oh by the way my hesitation is gone.I did end up with another issue but has nothing to do with Sea Foam. I just broke the vac line that goes from the front of the intake to the air control valve on the side of the p-pump. and i noticed there was p-fluid in the line which indicates the vale is leaking, which is why i some times had white smoke at start-ups."O.L.T." is responsible for this fix so im passing it on o the rest of the community that doesn't know about it. Here it is hope this helps out and saves money for every one who ever wondered about the issues i had been experiencing MERRY CHRISTMAS/HAPPY NEW YEAR ..https://www.clublexus.com/forums/per...s-one-out.html