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misses once warm

1K views 15 replies 7 participants last post by  foxneedswork 
#1 ·
Alright so my 90 fox runs like poop on any day that it's over 80 outside . So far I've replaced the tps, maf (sn95) , whatever the sensor us that mounts on the back drivers side. I've also cleaned the egr and iac as well as the throttle body itself. The car runs great save for a little bit of an idle hang until it's warmed up then it misses a bit at any throttle input. Almost like it can't see the TPS input. When this happens and I go to wot the car will appear to lean out and during this time the cel will come on for a second or two then go out once I'm out of wot . At night when cooler the car runs perfect. It has recently thrown codes 33 41 and 91, but now the 41 I'd gone since I re grounded the o2 sensor wire on the sensor side. At the pcm side it is grounded fine. Any thoughts to why this could be? Also timing is at 13 degrees and I'm running 92 octane
 
#6 ·
I'll go along with the coil or a small crack in the distributor cap.
 
#8 ·
Yes, they can do that even in the rain. Once a coil starts downhill it steadily and sometimes quickly gets worse.


That it gets so much worse in the rain is what makes me think that maybe the cap may be cracked, new or not. Humidity/water entering the cap can make it crossfire all over the place. The cap should also have a vent in it to keep ionization at bay.
 
#10 ·
You want the ones with the vent and brass contacts. Unvented and aluminum contacts just do not work as well.
Ionization occurs when the air inside the cap becomes electrically charged resulting in spark scatter or crossfire. It is more prevalent in smaller caps and in areas with higher humidity levels. A vented cap helps stir up the air to keep it from becoming charged.
 
#12 ·
Mine has some play too... But I replaced the coil cap and rotor dumped the codes and nothing changed... **** for fire and won't idle/run without me starting on the gas. I have a new hall effect sensor but haven't installed it. I can't run the koer test cause it won't run
 
#15 ·
I changed the pcv already. Also I pulled the dizzy, cleaned everything and replaced the tfi. I also reset the timing 14btdc, and it's running better but still not perfect. Still throws the 66 (either maf) and 91... As well as a 212 on the koer code. I'm gonna replace the hall effect switch and see that that does for the 212.
 
#16 ·
Another update... Installed a new dizzy, and USC... And it helped but it still hiccups here and there and hunts around for idle. It's at least drivable now but the only things I haven't done is check replace the oxygen sensors and eliminate the egr. This weekend I'll be swapping on a 98 explorer intake manifold and throttle body and eliminating the egr. I'll keep checking for replies/ideas and see what happens after the manifold swap
 
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