rough idle but no power
#1
Driver School Candidate
Thread Starter
Join Date: Dec 2013
Location: california
Posts: 22
Likes: 0
Received 0 Likes
on
0 Posts
rough idle but no power
i have a 92 sc400, i have replaced the o2 sensors, distributor caps, rotors, spark plugs and wires, and i just got done putting on a new upper intake manifold. but after i put it all back together it will start with a really rough idle around 3-400 rpm but it doesnt have enough power to move after i put it in drive or reverse. any advice will help! thanks.
#2
It sounds like a mass airflow sensor (MAS), try cleaning it but make sure you use a very specific MAS cleaner or you can damage it further. If that does not work then you will need to replace it. When I cleaned my MAS it worked for a few minutes then it went back to rough idle so I had to replace mine. Good luck!
#5
Intermediate
iTrader: (12)
I would check a few things regarding your issue:
- 1) Bad Catalytic Converter (maybe take it off and throughly clean it?)
- 2) ECU could be going bad, known to go bad on these cars and it cant regulate the idle RPM correctly.
- 3) Dirty or defective (MAS) Airflow Sensor
I just had to send my ECU to be rebuilt because I had irregular idle, no check engine light on startup, and odd shift times, and sounds like you have similar symptoms. Definitely check the other two thingsfirst!
Trending Topics
#8
In Recovery Mode
iTrader: (11)
It sounds like a mass airflow sensor (MAS), try cleaning it but make sure you use a very specific MAS cleaner or you can damage it further. If that does not work then you will need to replace it. When I cleaned my MAS it worked for a few minutes then it went back to rough idle so I had to replace mine. Good luck!
If your SC is 95 and later, feel free to spray down the MAF with liquid cleaner.
#9
Driver School Candidate
Thread Starter
Join Date: Dec 2013
Location: california
Posts: 22
Likes: 0
Received 0 Likes
on
0 Posts
thanks for all the help, i will have to check that stuff out. i cleaned off my mas so i ruled that out, next stop is to check the ignition coils. now if im not mistaken, the 92 doesnt have ignition coils it only has the spark plug wires. correct me if im wrong but they are one in the same correct?
#10
Driver School Candidate
Thread Starter
Join Date: Dec 2013
Location: california
Posts: 22
Likes: 0
Received 0 Likes
on
0 Posts
as far as a bad cat, i checked my exhaust flow and it seems normal. the problem only started after i replaced my intake manifold and replaced my spark plugs. so im thinking it would have to be something to do with either one of those
#12
Driver School Candidate
Thread Starter
Join Date: Dec 2013
Location: california
Posts: 22
Likes: 0
Received 0 Likes
on
0 Posts
it was running just fine before i changed spark plugs, and i only took one off at a time when i changed them so there was no way for them to get mixed up
#15
Lexus Champion
iTrader: (10)
Close but not correct. 92-95 is Karman maf. 96 And up is hotwire. You aren't supposed to clean the Karman with maf cleaner generally. The hotwire you can spray on the maf cleaner all day long. Both have air temp sensors also but thats not the problem.
You have 2 ignition cols. the wire that goes into the 2 distributors are the leads from the 2 coils. One of them is bad. Unplug one at a time to find the bad one. Report back. No need to look everywhere else it happens all the time.
You have 2 ignition cols. the wire that goes into the 2 distributors are the leads from the 2 coils. One of them is bad. Unplug one at a time to find the bad one. Report back. No need to look everywhere else it happens all the time.