weird off idle stumble/misfire

[lowandrusty]

Occasionally on my 182k mile '93 1.6 I'll get this weird hiccup when accelerating. Usually it happens just as I'm bringing the revs up and starting to engage the clutch so it doesn't affect driveability. (yet) My concern is that it will get worse though. My car is normally aspirated, with a racing beat header, magnaflow cat and 2.5 generic stainless exhaust. I've got fresh Ngk standard plugs, new-ish coil pack and Nology wires. Cleaning the throttle body and performing a seafoam treatment have done nothing to alleviate the condition. Any thoughts?

[RuckkehrMiata]

Could you describe the stumble more? I might not be much help myself but I know the very knowledgeable guys here will expect more information.

[lowandrusty]

Its just a momentary blip/hiccup. I can't even call it a misfire, more like a momentary gap in the ignition sequence. The car runs great otherwise, no rough running or misfiring. Hope that helps

[maharaj]

Are there any codes?

[KAL]

I have the same thing on my car (not a Miata). Possible solutions - fuel filter, throttle position sensor, ECU, coolant temp sensor. No codes.

[lowandrusty]

Nope, no codes.

[kung fu jesus]

i suspect it is ignition related. The coilpack may not be as healthy as anticipated. May be a CAS starting to fail. Maybe test the coils with a multimeter. Check your ground points, too. MAF may also be suspect.

[maharaj]

Has the fuel filter/pump ever been changed?

[lowandrusty]

i suspect it is ignition related. The coilpack may not be as healthy as anticipated. May be a CAS starting to fail. Maybe test the coils with a multimeter. Check your ground points, too. MAF may also be suspect.
I did check the coil, tests good. Haven't checked grounds though, I'll do that.


Has the fuel filter/pump ever been changed?

Did fuel flow, and pressure tests, both good.


I appreciate all the ideas people! Keep them coming!

[maharaj]

Was the car doing this prior to you changing the plugs, packs and wires? If not then I'd suspect once of those three.

[kung fu jesus]

Did you relocate, move or alter the MAF in any way or is it on the stock airbox/location?

[lowandrusty]

Was the car doing this prior to you changing the plugs, packs and wires? If not then I'd suspect once of those three.

Yeah, I've had the car for about 5 months and it's periodically done this sinc I purchased it.


Did you relocate, move or alter the MAF in any way or is it on the stock airbox/location?

No mods, other than the racing beat header and Nology wires. (old generic aftermarket wires came on the car)

[bradleynguyen97]

have you checked your tps?

[I<3flippyheadlights]

Change the wires to NGK blues. That should solve the problem

[lowandrusty]

Change the wires to NGK blues. That should solve the problem

I never had a problem running Nology wires in the past. I'm leaning towards the tps , or grounds being the issue. I've just been way too busy and haven't had a chance to get under the hood yet.

[maureen]

did you find any solution yet
mine is doing pretty much the same thing
when the weather is hot
rpm jumps from 2 to 3 up and down
but the speed stays at 60mph

[CeeJaayDM]

does it happen when taking hard left or right turns ?

while cruising does rpm suddenly drop then pick up ?

i had a problem similar to yours back then.

i would be driving at like 70-80 and rpm would drop down to 2k and jump back up with the slightest jerk ever.

on canyon runs i'd be at wot thru a corner and same thing would happen.

one time it got so bad to the point where if i would hit a dip my engine would just die.

i replaced fuel filter, coil pack, spark plugs and wires, also put my timing back to spec cuz i guess previous owner messed with it and problem solved lol. i had a 1.6

[toms96mx5]

I just had the same problem on my car, for me it was a plug wire that was shot. The one on my number 3 cylinder had burned/rusted through right where it connected to the plug, I had ordered some ngk blue wires what will be here in the next week but for now i just got a cheap set to hold me over.