Weird hesitation...WTF?!
Thread Starter
Instructor
Joined: Oct 2004
Posts: 187
Likes: 0
From: Port Saint Lucie FL
Weird hesitation...WTF?!
Someone please help!
I have a 99 mn6 FRC with nearly 50k miles and the car has a weird hesitation around 2200 RPMs ONLY WHEN HOT (up to temp @ *194 - 205*), & ONLY WITH LIGHT THROTTLE (maybe 1/5 of the way depressed w/ Granny 1 - 4 skipshifts and such). What's up? Coilpacks on their way out?
I have a 99 mn6 FRC with nearly 50k miles and the car has a weird hesitation around 2200 RPMs ONLY WHEN HOT (up to temp @ *194 - 205*), & ONLY WITH LIGHT THROTTLE (maybe 1/5 of the way depressed w/ Granny 1 - 4 skipshifts and such). What's up? Coilpacks on their way out?
Drifting
Joined: May 2003
Posts: 1,715
Likes: 1
From: cAshburn VA
Check your plugs and wires. Pull the plugs and look at them.
I had a similar issue after I switched to Taylor Thundervolts, probably a bad wire, switched back to my old low end taylors, problem gone.
If those are your original plugs and wires, I would probably have new stuff standing by when you pull them off.
Good Luck!
I had a similar issue after I switched to Taylor Thundervolts, probably a bad wire, switched back to my old low end taylors, problem gone.
If those are your original plugs and wires, I would probably have new stuff standing by when you pull them off.
Good Luck!
Thread Starter
Instructor
Joined: Oct 2004
Posts: 187
Likes: 0
From: Port Saint Lucie FL
I recently replaced the plugs and wires.
Maybe only 1500 miles ago, too. One thing I noticed is that the old plugs were "oil fouled". I assumed this was the "great PCV system" we have and disconnected it from the intake manifold and removed the dipstick and placed a breather on it maybe 250-300 miles ago. Maybe it is time for new plugs...again. And I was running NGK Iridiums which aren't cheap.
Maybe only 1500 miles ago, too. One thing I noticed is that the old plugs were "oil fouled". I assumed this was the "great PCV system" we have and disconnected it from the intake manifold and removed the dipstick and placed a breather on it maybe 250-300 miles ago. Maybe it is time for new plugs...again. And I was running NGK Iridiums which aren't cheap.
Melting Slicks
Joined: Mar 2005
Posts: 2,252
Likes: 181
From: NE OH
Could have an air leak.
During logging runs I've noticed a lean spike on my passenger bank at around 2K RPM. Pretty sure it's a vacuum leak as it isn't there when the engine is cold. When driving easy/slow you can feel the car hesitate when it hits this RPM range. It's also VERY noticable on the logs as the bank 2 STFTs go insanely positive and the WB goes lean. If I'm running hard, I can drive right through it like it isn't there.
During logging runs I've noticed a lean spike on my passenger bank at around 2K RPM. Pretty sure it's a vacuum leak as it isn't there when the engine is cold. When driving easy/slow you can feel the car hesitate when it hits this RPM range. It's also VERY noticable on the logs as the bank 2 STFTs go insanely positive and the WB goes lean. If I'm running hard, I can drive right through it like it isn't there.
Drifting
Joined: May 2003
Posts: 1,715
Likes: 1
From: cAshburn VA
what wires did you go to? Do you have headers? Are they heat shielded. If you still have your old wires, I would pop them back on for a test run. Very little effort to check that.
I am also running the NGK iridiums, was running Bosch Plat +4s before that, they were great until I went to 30# injectors and a speed density tune.
Good luck!
I am also running the NGK iridiums, was running Bosch Plat +4s before that, they were great until I went to 30# injectors and a speed density tune.
Good luck!
Melting Slicks
Joined: Mar 2005
Posts: 2,252
Likes: 181
From: NE OH
Originally Posted by rd122481
Air leak, huh? How do I check for that? Spray carb cleaner around the intake manifold and see if the idle "bumps up"?
Thread Starter
Instructor
Joined: Oct 2004
Posts: 187
Likes: 0
From: Port Saint Lucie FL
It's not spark plugs or a vacuum leak. IT'S A GRANATELLI MAF. I just called their service dept. and they said to remove my SuperChips tune, disconnect the battery(for an hour), replace their MAF with the stock one, drive for a day, then when I park it, remove the stock MAF and disconnect the battery AGAIN (for an hour), then replace the Granatelli MAF and all should be good. It seems like
to me. Why don't I just pull the Granatelli MAF and sprinkle it with a little fairy dust that Peter Pan gave me.
You guys think this will work?
to me. Why don't I just pull the Granatelli MAF and sprinkle it with a little fairy dust that Peter Pan gave me. You guys think this will work?
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Le Mans Master
Joined: May 2004
Posts: 5,683
Likes: 1
From: Houston Texas
Originally Posted by muncie21
Could have an air leak.
During logging runs I've noticed a lean spike on my passenger bank at around 2K RPM. Pretty sure it's a vacuum leak as it isn't there when the engine is cold. When driving easy/slow you can feel the car hesitate when it hits this RPM range. It's also VERY noticable on the logs as the bank 2 STFTs go insanely positive and the WB goes lean. If I'm running hard, I can drive right through it like it isn't there.
During logging runs I've noticed a lean spike on my passenger bank at around 2K RPM. Pretty sure it's a vacuum leak as it isn't there when the engine is cold. When driving easy/slow you can feel the car hesitate when it hits this RPM range. It's also VERY noticable on the logs as the bank 2 STFTs go insanely positive and the WB goes lean. If I'm running hard, I can drive right through it like it isn't there.