93 fox hesitates around 3500 rpm

[blufox62]

Hey Guys

my 93 hesitates when the cars gets to 3500 rpm. I have replaced the fuel filter, distributor(it was old anyway), cap,button, and wires. if i unplug the mass air flow sensor i still run into the problem. the funny this is that it runs like a champ until i get to the 3500 rpm mark. while hesitating it feels like a governor is installed and the Tach just goes up and down until i shift gears to get the rpms low.

when i ran the codes i came up with a code 91.

anyone seen anything like this? thanks in advance for your help

 

[jrichker]

The TFI module mounted on the distributor is usually the culprit for a high speed miss on a warm engine. If the problem does not occur when the engine is cold, the TFI module is definitely suspect. You may need a special socket to remove the TFI module, but most auto parts stores will have one for $5-$7.

Be sure to use plenty of the heat sink grease on the new TFI and clean the old grease off the distributor.

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