Better video of tach and audio of engine rough
View: https://youtu.be/zT0yKD1n9dM?si=7WqB5WGdMO7-Cr8j
View: https://youtu.be/zT0yKD1n9dM?si=7WqB5WGdMO7-Cr8j
85 GT intermittent miss at highway speed
- Thread starter rwordenjr
- Start date
Here's what I think, bad connection/wire in the ignition system or fuel delivery.
Try this, hook a timing light starting with #1 and see if any of the plug wires show an erratic light signal, point the light at a dark flat area and look for intermittent flashes.
Try this, hook a timing light starting with #1 and see if any of the plug wires show an erratic light signal, point the light at a dark flat area and look for intermittent flashes.
will try that. i ran koer again today and im getting 32 and 34 now . EGR codes. Could that make the car run rough, tach bounce, and die?
@General karthief i believe I found my problem. The 22k resistor from pin 5 of tfi connector to pin 4 of ecu doesn’t work anymore. It says 22k on it but no watts. Trying to find out how many watts for replacement
Found several saying its 1/2 watt.
https://www.allfordmustangs.com/threads/22k-ohm-resistor.297342/ Tom usually knows his stuff.
This thread should do it for you:
https://www.allfordmustangs.com/threads/22k-ohm-resistor.297342/ Tom usually knows his stuff.
This thread should do it for you:
Even a 1 Watt resistor is still really small. Like, 2mm longer than a 1/2 Watt.
You can get 100 of either one for about $6. You'll have some extras
You can get 100 of either one for about $6. You'll have some extras
New resistor put in… got 22k now from tfi module pin 5 to pin 4 of computer. Restarted car, no change in rough idle and car was still dying. Thought maybe those tfis and pip are now fried from the resistor not working for awhile… installed another reman distributor with pip and tfi I had (haven’t tried this one before) and we’re in business. Idling nice and tach steady. Going to test drive tomorrow during daylight.
There's a 'right way' to diagnose these problems, and it can be found in Jrichker's lists of the Surging Idle Checklist, the Crank, No Start checklist, etc... You can find quick links to that an a lot more in the "Technical thread/How-to Index thread at the top of the 5.0 forums.
That said, I've learned to keep 'known good' parts & the ability to bypass my MSD box readily at hand. When I start running into trouble like this, I can swap a dizzy, replace the injectors, Coil, EEC, plugs & wires, fuel pump, etc. etc... Just makes getting through things easier, but I still get stumped for a while from time to time. These cars can be very frustrating, and general automotive mechanics out there don't have the experience with them that the old crew did, anymore.
Hope this swap fixes it. Keep us up to speed. The last time this happened to me, I had to bypass the MSD box, but since I had it all wire tucked, it was tricky. eventually, I pulled the fender and bypassed until I could replace the MSD box. Now, I have an extension from MSD that allows me to quickly bypass if I ever run into anything, again.
That said, I've learned to keep 'known good' parts & the ability to bypass my MSD box readily at hand. When I start running into trouble like this, I can swap a dizzy, replace the injectors, Coil, EEC, plugs & wires, fuel pump, etc. etc... Just makes getting through things easier, but I still get stumped for a while from time to time. These cars can be very frustrating, and general automotive mechanics out there don't have the experience with them that the old crew did, anymore.
Hope this swap fixes it. Keep us up to speed. The last time this happened to me, I had to bypass the MSD box, but since I had it all wire tucked, it was tricky. eventually, I pulled the fender and bypassed until I could replace the MSD box. Now, I have an extension from MSD that allows me to quickly bypass if I ever run into anything, again.
Test drive complete. The miss that caused me to start this thread is gone and the car dying issue that evolved is gone too.
Did some more maintenance work today. Replaced what I believe is the original PCV valve/breather cap/hose as well as the EGR sensor to try to clear my KOER EGR codes. Also replaced the original TFI connector that I had been probing with needles for few days. Only 1 EGR code remains, code 32.
gkomo
now i can hopefully expect to receive the shaft
I’ll need to check later on. I recently had egr issues where the car started running bad and stalling out when idling. I scanned codes and only was egr stuff. I plugged egr vacuum and test drove… problem went away. I then replaced the egr itself and hooked vacuum line back up. Car has ran fine ever since
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