Car stutters/sputters for .5 sec but then is okay

The_Ghost

Registered User
I've had this problem for a few weeks now, and I am not sure exactly what it is.

It is a 1990 SC 5-spd, no mods with 192k miles.

What is happening is that every once in a while (but it seems like it's happening more frequently), the car seems to "miss" one beat and then goes back to normal, and runs fine again. Basically it just falls on its face for possibly one compression cycle, I suffer a slight (miniscule if any) drop in RPM for less than half a second (but just long enough to give the car a jolt) and then resumes running as if nothing were wrong, and I have not gotten any CEL codes.

Any ideas as what these symptoms would indicate?

Thanks,
Ghost
 
hmmm... how old are your plugs and wires??? anywho... i say it might be ur crank sensor! or cam position sensor... maybe tps... you say you dont get any CHECK ENGINE LIGHT right? maybe there are some codes stored but didnt throw off any light... you should try running a KOEO test and a KOER test and see if it works... let me know if u need more help..
 
crank and cam sensors were changed by previous owner, and previous owner claims plugs were changed recently. I have driven the car like 6,000 miles since I bought it, and having worked at autozone it has come to my attention that many mechanics cheap out and will not put the required platinum plugs into a car.

The car has been apart at some point, since I am averaging 17mpg city at 192k miles, and the PCV line that normally runs under the SC is sitting on top of it.

I have a set of new-in-box champion double platinums, because I wasnt able to find motorcraft dbl platinums and the champions have an unconditional 5 year unlimited mileage guarantee, which I fully intend to abuse.
I haven't changed them because, to be totally honest, I am very intimidated by just looking at the engine bay. I can't even SEE the spark plugs. I really should get to changing them but they scare me. Suggestions so far as that go would be greatly appreciated.

I have not changed the plug wires, so that might be a possibity. A good way to check would be to run the car with the hood open w/o the engine light on, and see if I can see any light or electricity jumping to grounds off the cables. (this happened a LOT amongst the 280ZXs I've worked on, even with month old wires for some reason)

In response to BT motorsports,
I am not sure it would be an ignition cylinder since I have changed the switch and the lock cylinder and replaced them with the new parts. If that's not it, then you must be referring to a different part than what I am referring to as the 'ignition cylinder'.

Again, this problem occurs while driving after the car's been driving for 20-30 minutes, and only does it while the car is in gear, and in a steady-state cruise. It'll do it maybe once, and then I won't hear from it again for the entire rest of the trip or for a couple of days, but today I had it do two stutters in a row under boost on the way to work today, so now I am starting to get concerned. It hasn't shown up again on the way home even with the slow-n-go I put it through on the 405 along with sudden deliveries of 10psi, but that really alarmed me.

I should probably run a cylinder balance test, but I just wanted to know if what I'm experiencing is symptomatic of any particular problem/condition.

-Ghost
 
This was happening to me on every outing a few years ago. Not sure how this had anything to do with it but after I replaced the battery (and I only touched the battery) not a single sputter since. If you've had the battery for a while try getting a new one.
 
I have a set of new-in-box champion double platinums, because I wasnt able to find motorcraft dbl platinums and the champions have an unconditional 5 year unlimited mileage guarantee, which I fully intend to abuse.

Don't use those even if you do feel like abusing the warranty. Go get some proper plugs
 
Okay, well, I've still got the reciept and they're all still in the box.

Who (in Los Angeles, CA), or more specifically, which chain sells the Motorcraft Double Platinums?

As a comment to the battery thing, actually it's funny you say that, the car had a 34-series battery in it with the poles reversed, and apparently the car calls for a 65 series? The 65 series sits EXTREMELY high in the bay and the positive terminal keeps wriggling itself off of the post. I tighten it down but it keeps just barely jumping off. That might have something to do with it.

Thanks,
Ghost
 
Get a set of Autolites for the car, as they are very good as well... Here's a post from LJGriggs about which ones depending on what you want.

"AutoLite #APP 2544 (stock replacement/long end)
AutoLite #APP 764 (Short end/one range cooler)
AutoLite #APP 103 (short end/two ranges cooler)

I prefer the APP764 plugs but any of these should work for you. (The APP103 may be better for highly modded engines.) Just stay away from Bosch plugs... They don't work well in our cars."


Personally I prefer using the copper equivalents both in my LX and the SC as I don't mind pulling plugs every year to see what is happening inside...... use the plugs for a health monitor so to speak.
 
copper works well as well as iridiums. I use ngk iridiums and they work great. If all else fails goto ford for the plugs
 
you need to watch the tachometer while the jolt or miss is happening. If the tach falls and rises as quickly as the jolt happens, then you have a crank trigger problem(crank sensor). If not its likely a plug wire. Crank or camshaft sensors usually wont set a code in the eec system until they are of hard fault status (completely inoperative). You need to take all the champion plugs off the shelf at your parts store and throw them directly in the dumpster out back. They might work ok in you lawn tractor, but never in a ford. Motorcraft or autolite only. Autolite makes motorcraft so they are one in the same. Champion, bosch, ngk, etc have no place in your ford. Any one who knows like i do about obd2, eec-v, and misfire monitors will tell you the same. If none of this helps you. Id drop it off at the local ford dealer and pay the diagnosis fee of 60-90 bucks. Its a hell of a lot cheaper than guessing. Then you can buy what you need and fix it yourself.
 
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