Engine 1990 5.0 Engine "stutter" miss

KaptKane · Jun 25, 2019

Newb here. My 90, 5.0 5 speed has developed an occasional "stuttering" type of engine miss at low RPM and lite throttle. Running it up through the gears at full throttle (thru 3rd anyway) it seems to run smooth and strong like it always has. I only seem to get that "stuttering" miss when like cruising on a city street and I shift up to 5th and the RPMs drop around 1300/1400 and lite throttle just to keep up with traffic. Its intermittent and I can't "make" it happen.
Supposedly (as told to me by the guy I bought it from) it has a 303 cam and Explorer upper/lower intake and this "Intense Tuning" module. (please see attached pic)
All my years of fooling with cars told me it was a plug wire going bad. So, I put new plugs, wires, distributor cap and rotor. The miss is still there!
Incidentally, when I changed the plugs, all were burning that nice light tan color except #4. It was definitely darker (almost black) like it was burning more rich than the other cylinders.
Ideas?
Thanks in advance.

General karthief · Jun 25, 2019

I would start with a compression test to see if you have a problem in that one cylinder.
there is a thread here that can help save you from chasing your tail and wasting money.

Help me create the "Surging Idle Checklist"

Updated 26-Oct-2019 to clarify creeping idle RPM increase as the car is being driven. Many of you are familiar with the "Cranks OK, but No Start Checklist for Fuel Injected Mustangs" checklist and the No Crank Checklist. They are very effective in finding and eliminating the problems by use of...

forums.stangnet.com

Start at the top and do it step by step. Don't skip around, the next step depends on the result from the previous one.
Jrichker put it together ant it works.

Real time recon · Jun 27, 2019

I had a problem like you mention.I took the MAF sensor off (cleaned it with the "proper" spray cleaner). IT looked "clean" (before I cleaned it) ,but I figured W.T.H and did it anyhow. after it was cleaned, I noticed a Hugh difference in how clean it was...........Reinstalled MAF sensor 1/2 hr later after it was completely dry..........and problem solved.! Purrs like a kitted

KaptKane · Jun 27, 2019

Awesome! So...what's the "right" cleaner? Carb cleaner? Electrical cleaner? I sure hope my reacts the same as yours did!
Thanks.

Real time recon · Jun 27, 2019

KaptKane said:
Awesome! So...what's the "right" cleaner? Carb cleaner? Electrical cleaner? I sure hope my reacts the same as yours did!
Thanks.

CRC >> View: https://www.youtube.com/watch?v=o90KcZRz95U

KaptKane · Jun 29, 2019

So...I removed the MAF and sprayed it good. Replaced it after I was sure it dried good. Drove it 60+ miles this morning and (knock on wood) it hasn't acted up!
Thanks for the tip. If anything changes, I'll be sure to post because I'll be looking for help!

Real time recon · Jun 29, 2019

KaptKane said:
So...I removed the MAF and sprayed it good. Replaced it after I was sure it dried good. Drove it 60+ miles this morning and (knock on wood) it hasn't acted up!
Thanks for the tip. If anything changes, I'll be sure to post because I'll be looking for help!

Glad to hear that ! I'm thinking these air filters (come from the factory) coated with a very thin coat of oil (to help keep out dirt/dust) and THAT oil over time gets sucked into the MAF sensor.

Real time recon · Jun 29, 2019

Also sometime take a look at the PVC Valve and filter/screen that's just under the PVC valve.Here's pix. of the old and new one(old on the right,new one on left) .
See how dirty the old screen is.........

Blown88GT · Jun 29, 2019

KaptKane said:
Newb here. My 90, 5.0 5 speed has developed an occasional "stuttering" type of engine miss at low RPM and lite throttle. Running it up through the gears at full throttle (thru 3rd anyway) it seems to run smooth and strong like it always has. I only seem to get that "stuttering" miss when like cruising on a city street and I shift up to 5th and the RPMs drop around 1300/1400 and lite throttle just to keep up with traffic. Its intermittent and I can't "make" it happen.
Supposedly (as told to me by the guy I bought it from) it has a 303 cam and Explorer upper/lower intake and this "Intense Tuning" module. (please see attached pic)
All my years of fooling with cars told me it was a plug wire going bad. So, I put new plugs, wires, distributor cap and rotor. The miss is still there!
Incidentally, when I changed the plugs, all were burning that nice light tan color except #4. It was definitely darker (almost black) like it was burning more rich than the other cylinders.
Ideas?
Thanks in advance.

Bad News.

Intense Tuning Performance Module – Performance Chip Reviews

KaptKane · Jun 29, 2019

Thanks for the update. I was being "cheap" and figured I could pick up another 10hp for $20. I guess I got what I paid for!
If you look at my updated pic in the thread (that shows the can of CRC MAF Cleaner sitting atop the MAF housing) you'll notice that the "Intense Tuning" module is gone. I removed it as part of trying to get me engine running correctly again.

jrichker · Jun 29, 2019

You guys with idle/stall problems could save a lot of time chasing your tails if you would go through the Surging Idle Checklist. Over 50 different people contributed information to it. The first two posts have all the fixes, and steps through the how to find and fix your idle problems without spending a lot of time and money. It includes how to dump the computer codes quickly and simply as one of the first steps. I continue to update it as more people post fixes or ask questions. You can post questions to that sticky and have your name and idle problem recognized. The guys with original problems and fixes get their posts added to the main fix.

It's free, I don't get anything for the use of it except knowing I helped a fellow Mustang enthusiast with his car. At last check, it had more than 250,000 hits, which indicates it does help fix idle problems quickly and inexpensively.

Noobz347 · Jun 29, 2019

jrichker said:
You guys with idle/stall problems could save a lot of time chasing your tails if you would go through the Surging Idle Checklist. Over 50 different people contributed information to it. The first two posts have all the fixes, and steps through the how to find and fix your idle problems without spending a lot of time and money. It includes how to dump the computer codes quickly and simply as one of the first steps. I continue to update it as more people post fixes or ask questions. You can post questions to that sticky and have your name and idle problem recognized. The guys with original problems and fixes get their posts added to the main fix.

It's free, I don't get anything for the use of it except knowing I helped a fellow Mustang enthusiast with his car. At last check, it had more than 250,000 hits, which indicates it does help fix idle problems quickly and inexpensively.

You mean the one from post 2?

Engine 1990 5.0 Engine "stutter" miss

KaptKane

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General karthief

wonder how much it would cost to ship you a pair

Help me create the "Surging Idle Checklist"

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Engine 1990 5.0 Engine "stutter" miss

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