94 stumbles when cold
Thread Starter
2nd Gear
Joined: Jul 2012
Posts: 2
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94 stumbles when cold
I have a 1994 6spd coupe with 145,000 miles that stumbles and runs rough when driven cold. When the engine temp hits 160 degrees everything smooths out and the revs freely. any ideas what this could be?
Safety Car
Joined: Sep 2010
Posts: 3,752
Likes: 190
From: Indiana PA
I can tell you this it is probably running lean and goes into closed loop around 160, it then sees this via 02 feedback and makes adjustments.
Does it sound like it is back firing thru the intake when you try to accelerate when cold?
Does it run bad cold all the time? Does it run bad if you go to WOT when below 160?
No codes I assume?
Start with fuel pressure and go from there.
You WILL need a decent scan tool and someone who knows what they are looking at to go over the ECM input data to make sure it is on the up and up.
You might try picking up a can of MAF cleaner and cleaning your Mass Air Flow meter.
Good Luck.
Thread Starter
2nd Gear
Joined: Jul 2012
Posts: 2
Likes: 0
I have not checked the codes but it does sound like it is backfiring through the intake when I accelerate. It does this all the time when cold and if I try WOT it will stumble When pulling out into traffic before the engine temp gets to 160 degrees can get very interesting. I will try the MAF cleaner and clean the MAF meter. If all else fails there are several corvette specialists in my area.
Thank you
Thank you
Advanced
Joined: Mar 2009
Posts: 90
Likes: 0
stumble
I have not checked the codes but it does sound like it is backfiring through the intake when I accelerate. It does this all the time when cold and if I try WOT it will stumble When pulling out into traffic before the engine temp gets to 160 degrees can get very interesting. I will try the MAF cleaner and clean the MAF meter. If all else fails there are several corvette specialists in my area.
Thank you
Thank you
Race Director
Joined: Mar 2015
Posts: 15,926
Likes: 579
