3.2 Stutter During Hard Acceleration?

[Jgordon]

New and interesting problem. Within the last year or so, I've developed an issue. Occasionally, and that's the frustrating part, when I'm accelerating, the engine will simply cut out around 2500 or 3k, gear-independent. It basically pauses for a minute, with the gas pedal doing nothing, and then it will catch again and I can continue up through the power band. I haven't been able to repeat it at will, and it's an odd sensation, so I'm unable to give any more specific feedback.

Engine is a 3.2 bumped to 3.4, single plug, relatively new distributor and wires, Steve Wong chip put in about 2006.

Car is at Rudtner's as we speak for unrelated issues, but I did ask him to look at the AFM arm issue that's popped up. He's replacing plugs and fluids, doing normal 15k service stuff. That may solve the issue without focusing on it.

Any other possibilities or areas of focus?

Thanks.

[911 Rod]

How does it run in the rain?

[Pedro '84 Coupe]

Had a similar issue on my '84. Thought it was a bad DME relay but turned out to be a clogged fuel filter.

[jpnovak]

This could be due to worn carbon traces on the AFM resistor board. There are ways to reclock the AFM wiper arm and provide a fresh surface. This requires AFM disassembly.

The rpm band you describe is where most engines spend their time cruising. This is what wears the track.

[rsscotty]

One thing to look at is the inside of the ignition coil tower where the coil wire plugs in.

Even though you have new wires, this visual coil inspection may have been overlooked.

The coil is mounted up high with a plastic cover over it, so it is one of those areas that is not easily seen without a mirror or taking the coil off its mount.. I have seen a few with the typical green/white corrosion that was so bad I was surprised it ran at all, but caused occasional throttle response issues.

[911 sc]

I had some of the same issues mine was a combination of clogged fuel filter, bad negative battery cable and my flywheel sensors were shot.

[Jgordon]

Originally Posted by 911 Rod

How does it run in the rain?

Runs fine in the rain.

[Jgordon]

I'll ask Bill to look at all of this. Can't hurt.

Appreciate the thoughts.

[Tippy]

I had the same problem and never resolved.

My last logical thought was my alternator had went out (brushes too worn), and the DME really doesn't like lower voltage.

[Jgordon]

Originally Posted by Tippy

I had the same problem and never resolved.

My last logical thought was my alternator had went out (brushes too worn), and the DME really doesn't like lower voltage.

Had the same problem? Went away on its own? Or you still have it?

Most of the above has been addressed by the 15k service bill did. The afm track is an interesting possibility. If the problem persists I'll try that next. Will report back in any case.

[Tippy]

Originally Posted by Jgordon

Had the same problem? Went away on its own? Or you still have it?

Most of the above has been addressed by the 15k service bill did. The afm track is an interesting possibility. If the problem persists I'll try that next. Will report back in any case.

About 6 months of hell never resolving. I have a thread if you search 'driving my 3.2 off a cliff', or something to that effect.

I pulled out the DME and put in MegaSquirt II.

[T77911S]

crank position sensors.

[GH85Carrera]

My car did that. It was the coil. Replaced with the old stock black OEM coil, problem solved.

[Tippy]

^^^ Let the shotgun diagnostics begin!!

[Bob Kontak]

Originally Posted by Tippy

^^^ Let the shotgun diagnostics begin!!

Bwa Ha Ha Ha.

Do the night time check of your engine bay for the potential light show. Rev it up once your eyes adjust to the darkness. The stutter is what triggers this for me.

My coil secondary would arc to one of the primary posts only on hard accel which also presented itself when I would blip engine when testing. Your symptoms don't quite sound the same as mine as it was a huge sensation of deceleration, I would lock the seatbelts from lurching forward.

You could see it in the daytime but I suggest the night time check to just put that variable to bed.

How's that for shotgun?

[DutchessCo]

Had a similar issue and it was a loose connection on the starter and was creating an intermittently bad ground.

[Tippy]

Originally Posted by Bob Kontak

How's that for shotgun?

Starting off 4-10 there, Bob!

I got up to 12 gauge.....

[T77911S]

Originally Posted by Tippy

^^^ Let the shotgun diagnostics begin!!

I am very much against it and prefer to do as much testing as possible before spending $$. sometimes there are fixes that educated guesses based on symptoms and prior experience.

[stlrj]

Originally Posted by T77911S

I am very much against it and prefer to do as much testing as possible before spending $$. sometimes there are fixes that educated guesses based on symptoms and prior experience.

Another reason to get into a newer ride that has on board diagnostics. Meanwhile we settle for educated guesses.

Cheers,

Joe

[Bob Kontak]

Originally Posted by stlrj

Another reason to get into a newer ride that has on board diagnostics. Meanwhile we settle for educated guesses.

Give me an old 911 any day.

Customer brings in his 2003 Lincoln Navigator which I have a professional scanner for. Traction control is trying to engage but cant. Grindy noise in left front wheel where advance traction is trying but can't.

One "real" ABS code. Voltage out of range. Battery on the ragged edge.

Bus link/CAN communication errors in three different modules. 4x4 module wont communicate with scanner at all. Clear all codes and car does well until it rains.

After a day of fiddling customer says "When it rains, I get water all over the floor on the driver's side." Just kill me. Thanks for that tidbit.

Ford wants about $2500 for that fix. Couple of modules/fuse box and entire under dash harness replacement along with windshield. Assuming that is the problem.