strange misfire

stang9150

Member
Dec 26, 2005
137
1
18
Can not figure this one out.I will start the car up drive about 5 minutes and the car will just start missing it will do this for about another 5 minutes and run normal until i shut the car off.I even turned the car off at a redlight and then restarted and it went through the same scenario.It does not matter how long the car sits 5 seconds to 5 hours same thing everytime.It breaks up at idle and everywhere else in the rpm range.If iam driving it starts to breakup if i just mantain speed i will hear and feel it missing then its like a light switch and i feel everything go smooth and run normal.
 
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RatStang

New Member
Feb 11, 2010
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Pull codes

+1

2. Check condition and connections for TFI, coil, spark plugs, and grounds
3. Then disconnect the EEC, clean the terminals and reinstall. Check for hole in EGR diaphram.
4. Shake rattle and roll wiring harness at all accessible locations while listening for change.
5. Replace TFI, plug wires, cap and rotor (unless brand spankin new and known to be good). Don't assume spark plug wires are good if they're more than say, a year old (ask me how I know).


Wild Ass guess??? TFI module bad.
 

stang9150

Member
Dec 26, 2005
137
1
18
The codes did not come up with anything besides smog equipment junk which has been off since 2000.My original thought was the tfi module but from all the reading i have done they either work or dont.I dont think it is the wires because its like a time clock 5 minutes runs great 5 minutes of missing then run normal till when ever i turn the car off.I will try some of the things you guys have mentioned,thanks for the help
 

stykthyn

I want to measure mine. It doesn't look that tall.
10 Year Member
Jul 6, 2006
5,298
2,727
223
gainesville
mine did that. was the TFI. Could also be the pickup in the distributor.
 

stang9150

Member
Dec 26, 2005
137
1
18
yeah i was going to look at the pick up also.Thanks i will give this stuff a try this weekend and report back
 

stang9150

Member
Dec 26, 2005
137
1
18
well it ran good for a few days now the issue is back.Iam thinking it could be the o2 sensors.I drove with them unplugged and the breaking up did not happen.Plugged them back in and it came back.The funny thing is even with the o2s unplugged i do not get a check engine light.I am going to leave them unplugged this week and see what happens.