Performance & Maintenance Engine, forced induction, intakes, exhausts, torque converters, transmissions, etc.

Need Advice SC400 stumbling

Thread Tools
 
Search this Thread
 
Old 03-04-12, 03:54 PM
  #1  
RudysSC
Pole Position
Thread Starter
 
RudysSC's Avatar
 
Join Date: Feb 2012
Location: CO
Posts: 2,384
Received 1,197 Likes on 830 Posts
Default Need Advice SC400 stumbling

So it started slowly last night and progressively got worse. The car stumbles (feels/sounds) like it's missing at idle. It gets worse under light load/acceleration. However, as soon as you hit the gas hard it pulls just fine all the way to redline, shifts fine etc. I pulled the plugs (which i replaced the other day, and it ran perfect afterwards, and also passed emissions flawlessly the next day) and they are white. So obviously it's running lean, but i'm not sure why. I'm thinking maybe a clogged fuel filter? Maybe a bad MAF?

Any suggestions would be kindly appreciated. Thanks you guys.
Old 03-04-12, 08:25 PM
  #2  
RudysSC
Pole Position
Thread Starter
 
RudysSC's Avatar
 
Join Date: Feb 2012
Location: CO
Posts: 2,384
Received 1,197 Likes on 830 Posts
Default

Just changed the fuel filter and nothing. Any ideas?
Old 03-04-12, 09:36 PM
  #3  
JDMmuscle
Lexus Champion

iTrader: (9)
 
JDMmuscle's Avatar
 
Join Date: Feb 2007
Location: State College, PA
Posts: 2,146
Likes: 0
Received 6 Likes on 6 Posts
Default

How many miles and what year? Can you get a video of this?
Old 03-04-12, 09:56 PM
  #4  
xxtoobsxx
Lexus Champion
iTrader: (4)
 
xxtoobsxx's Avatar
 
Join Date: Jun 2007
Location: ca
Posts: 2,150
Likes: 0
Received 2 Likes on 2 Posts
Default

Check the timing!!! my guess is you might be a tooth or 2 off
Old 03-04-12, 11:23 PM
  #5  
RudysSC
Pole Position
Thread Starter
 
RudysSC's Avatar
 
Join Date: Feb 2012
Location: CO
Posts: 2,384
Received 1,197 Likes on 830 Posts
Default

It's been driving fine for weeks since i've bought it until last night. i can't imagine the belt could have hopped a tooth or something. wouldn't that throw a CEL also?

It's a '96 w/59k miles.
Old 03-05-12, 03:00 AM
  #6  
mtnrat
Pole Position
iTrader: (1)
 
mtnrat's Avatar
 
Join Date: Jul 2008
Location: BC
Posts: 254
Likes: 0
Received 0 Likes on 0 Posts
Default

mine skipped a tooth on the cam at 48000 miles last summer. Before that I checked everything to find the hesitation. Just check the timing to rule it out. Could save you a lot of time looking.
Old 03-05-12, 09:16 AM
  #7  
RudysSC
Pole Position
Thread Starter
 
RudysSC's Avatar
 
Join Date: Feb 2012
Location: CO
Posts: 2,384
Received 1,197 Likes on 830 Posts
Default

I'll do that today for sure. Also going to throw fresh gas and some BG44k in just for reassurance that it's not bad gas or something.
Old 03-05-12, 04:38 PM
  #8  
RudysSC
Pole Position
Thread Starter
 
RudysSC's Avatar
 
Join Date: Feb 2012
Location: CO
Posts: 2,384
Received 1,197 Likes on 830 Posts
Default

After everything still ran like ****, timing was fine etc etc. Pulled the #5 and 7 plugs out (where the misfires were) and it ran just fine with new plugs. WTF. Oh well.

By the way, anybody done caps rotors etc themselves? I don't think i need them, but it might not hurt to do soon.
Old 03-05-12, 06:47 PM
  #9  
mtnrat
Pole Position
iTrader: (1)
 
mtnrat's Avatar
 
Join Date: Jul 2008
Location: BC
Posts: 254
Likes: 0
Received 0 Likes on 0 Posts
Default

Cracked plugs? Glad you found the problem. Finding hesitation can be a b!t(#.
Old 03-05-12, 06:51 PM
  #10  
1JZPWRD
1JZ Single SC400
iTrader: (59)
 
1JZPWRD's Avatar
 
Join Date: Jan 2009
Location: Alabama, Roll Tide!
Posts: 8,518
Likes: 0
Received 15 Likes on 12 Posts
Default

Glad you found the problem. Gotta love the forums.
Old 03-05-12, 08:52 PM
  #11  
MooJohn
Lead Lap
 
MooJohn's Avatar
 
Join Date: May 2011
Location: GA
Posts: 485
Likes: 0
Received 2 Likes on 2 Posts
Default

With the age of the car, caps & rotors are a good idea anyway. They're available at any parts store.
Old 03-06-12, 04:58 PM
  #12  
RudysSC
Pole Position
Thread Starter
 
RudysSC's Avatar
 
Join Date: Feb 2012
Location: CO
Posts: 2,384
Received 1,197 Likes on 830 Posts
Default

Thanks guys, go figure right? MooJohn, how hard of a job is it? I'll search and see if there are any DIY's. Thanks guys, loving this forum more and more every time i hop on.
Old 03-07-12, 12:29 PM
  #13  
ihiryu
Lexus Champion
iTrader: (7)
 
ihiryu's Avatar
 
Join Date: Oct 2007
Location: tx
Posts: 1,668
Likes: 0
Received 2 Likes on 2 Posts
Default

Not bad, removing all the covers is the hard part. You've gotta take the plastic covers on the bottom, once you get those outta the way, it's like two screws per side and done.
Old 03-07-12, 01:51 PM
  #14  
RudysSC
Pole Position
Thread Starter
 
RudysSC's Avatar
 
Join Date: Feb 2012
Location: CO
Posts: 2,384
Received 1,197 Likes on 830 Posts
Default

hmmm. word. might have to try and knock this out soon! it'll have to be in a few weeks, but it sounds like a good idea to get it done.

Thanks again everyone, much appreciated!
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
bboykid10
Performance & Maintenance
6
12-01-22 08:12 PM
Swint
Performance & Maintenance
26
09-09-13 12:32 PM
luvmyaussy
Performance & Maintenance
5
07-19-11 05:25 AM
IS_250
Performance & Maintenance
23
02-28-11 08:51 PM
DETONATION
Performance & Maintenance
13
12-26-08 07:06 PM



Quick Reply: Need Advice SC400 stumbling



All times are GMT -7. The time now is 08:28 PM.