97 Cobra hesitation low rpm/high gear


New Member
Feb 25, 2017
Hi everyone,
My 97 Cobra has a hesitation under load when driving in high gear/low rpm. In 5th if I am cruising and say I am going at like 60 and rpms are under 2000 rpm and I floor it the engine hesitates. Also does it in 4th when rpms are low. It idles fine and pulls fine when taking off rowing through the gears up to red line. The IMRC seems to be transitioning as I feel the surge above 3200 rpm. I have replaced wires, plugs, coils, air filter, fuel filter 10k ago, cleaned MAF sensor, tried techron, seafoam intake. When I first did those above it seemed to clear up, now it has returned after sitting for a month while winter weather is here. I am thinking about trying That CRC induction cleaner for gdi engines since they suffer carbon build up behind the intake valves, like the IMRCS do. I just wanted opinions if anyone has tried that product vs seafoam. I appreciate all responses, thanks.


Slow mustang :(
Established Member
Sep 18, 2002
Los Angeles
3 possible cuplrits (from my personal experience). I chased a low rpm hesitation for a few years.

1. EGR (not likely)
2. EGR vacuum solenoid (VERY likely)
I would not buy a used one.. this is something you buy brand new replacement.
3. Vacuum hoses (very possible) [small hard, some are red, others green], have a nipple where they plug into a rubber boot that attaches to either a solenoid, egr or other vacuum pieces. Make certain that they are NOT bottomed out against the inside wall of the curved rubber boot..for example right above the EGR spaceship, the boot plugged into the vacuum line has a 90 deg bend. Pull the vacuum line out a little until the slight bulge in the vaccum line is at the edge of the boot. If the bulge is not visible, the hose is most likely bottomed out.

cbr repsol

Well-Known Member
Established Member
Jun 21, 2006
Do you know where I can get the factory vacuum hard plastic line that goes to the egr vacuum solenoid ? Or just use some small rubber vacuum hose?

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