Engine Miss At Idle

MY90SC

Registered User
help for possible new member

I ran across a guy yesterday that has a black 93 here in my area he has been having some problems with a rough idle or a miss.
he has done
DIS Module
crank sensor
o2 censors
plugs wires
plugs again

still has stock exhaust
he has added a K & N cone filter on to the stock sampling tube right after the MAF( it looked like a Jerry rig Job)
he told me that the MAF was cleaned and it seemed to help but not fix the problem

with no luck getting it to run smooth
this engine is a reman from Ford with minimal miles on it since the install. If it is a miss could it be an injector??
any ideas or suggestions would be muchly appreciated
 
he has added a K & N cone filter on to the stock sampling tube right after the MAF

Ron,

You lost me there for a second. You obviously mean he has added a K&N BEFORE the MAF, and you mentioned a stock sampling tube. Does he have an aftermarket MAF, or do you mean he has a stock MAF?

Could be an injector, but we let is know on the above.

Regards,
 
the guy has attached a cone filter to the stock MAF. so there is no sampling tube right
what I was referring to was the intake pipe which is also stock.
oh and even though he got rid of the stock airbox the air silencer is still there We need to help this guy.
 
Ron,
I have been running a cone filter on the stock maf for the last 1500Km since I did HG and if anything I'm finding the car is running better but still a little rich on fuel.
 
I OWN A 93 S/C....I LOVE THE CAR...I HAVE REPLACED THE TRANNY(AUTO)...DROPPED IN A LONG BLOCK FPURCHASED FROM FORD...CARRYING A 2 YR WARRANTY....HAVE REPLACED CRANK...CAM...O2..ENGINE COOLANT TEMP...AND OIL PRESSURE SENSORS....BUT FOR CRYING OUT LOUD..I STILL HAVE A MISS AT IDLE.ALL MY PLUGS AND WIRES HAVE "JUST "BEEN DONE...ALL OEM EXCEPT THE 02 SENSORS.I AM IN NEED OF A CURE.ANY POSSIBLE SOLUTIONS WOULD BE GREATLY APPRECIATED.I AM L NEW HERE...BUT WOULD LIKE TO DRIVE MY CAR WITH FULL CONFIDENCE IN MY MOTOR AND ALL ELECTRONICS. CAN SOMEONE PLEASE HELP ME..."PLEEEAAASSEE"!!!!!!!
 
Welcome to the club

Hey Nathan its Ron

you might want to turn your caps off to type.

I already started a thread trying to get some help for you maybe one of the moderators could join the 2 threads to save room on the board.

anyways I'm sure that someone can peg it down for you.

enjoy
:)
 
things ive learned to check.

IAC,

DIS and your coilpack

have you scanned it for codes?
 
Hi Nathan.

Which plugs are you running (34pp's?), and what are they gapped at right now?

Hopefully, we'll help you get this resolved so you can enjoy the car a little more.

Welcome to the club!

Cheers,

Sean
 
Ron,

The threads have been merged.

Nathan,

As I've learned from my recent experience, this miss could be due to a valve not closing/sealing properly. I would do a compression test (you can buy the tool at Canadian Tire) on each cylinder to make sure you do not have one weak cylinder.

After that, you can start pulling plug wires off of the coil pack one at a time while the car is idling to try and isolate which cylinder is missing. Make sure you ground the open coil when doing this, so the voltage has somewhere to go.

Once you isolate a cylinder, you can may need to remove that injector and have it tested. There may or may not be a quick fix to this problem, so be patient.

I vacuum leak causes the car to run rough, which may simulate a miss depending on the severity of the leak. I would spray some TB cleaner on all your connections to rule this possibility out first and foremost.

Good luck!
 
Last edited:
Nathan welcome to the club

Just to let you know if you do go for doing a compression test all that kind of stuff is on sale right now at Canadian Tire for the rest of this week.

Best of luck with geting it running.
 
Bill I checked his gauge he is running 18-19 on the vac side at idle I know his gauge could be out but it would suggest that a vac leak is not the culprit. I think it may be his MAF or an injector or maybe it is the filter setup he is running I have never seen it done like that before there is actually a jerry rigged bracket to hold up the MAF and the cone filter. which had to bent slightly to fit.
 
Ron,

I know exactly which kit you are speaking of, because that was the first mod I ever did to my car. K&N makes the kit, although they specify it is not for the SC, but it does fit. There is nothing wrong with having the filter right at the MAf like that, unless I'm missing what you are trying to say.

If he has good vacuum, then move onto other possibilities. I would suggest trying the compression test and isolate a cylinder before going in the wrong direction.
 
cylinder balance test

You can do a cylinder balance test using only a clipl lead, the ECM runs and shuts off one Cyl at a time to look at the difference in RPM.
 
Back
Top