Alight here's the deal randomly my car has a mind of it's own but here's what happens. My car will go into a limp mode once the car gets hot enough for the fan to kick on and continues to kick on example 5oclock traffic n stop lights. Limp mode meaning it will start sputterig an not excellerate. And then it will stop and be fine again. What could it be? Fan relay? The fan turn on switch the temp sender? Ecu? What anyone else have the problem? Any input would be awesome.

 

Is there a coolant temp sensor in the intake right by/at/on the thermostat housing? Some V8 cars have one, tells the computer coolant temps and computer changes tuning accordingly - might be bad. If like a V8 car, would have a black wire and yellow wire to it.

 

alright i will try that any other suggestions?

 

You do realize that in limp mode the fan is always on so it's probably limp mode triggering the fan, find out why it goes into limp mode.

 

I have a bad ecm, because of the ground so the fan is ALWAYS ON, bypasses... any good fix for cheap?

 

no the fan comes on then eventually it will go into limp mode. then start running fine and the fan doesnt necessary kick back on for it to start being in limp mode again

 

yo dude. i had to register now coz i have the same problem with my car. i own a conquest 4age 20valve. did you solve your problem yet

 

okay so i had the same problem and had to get a piggyback because my PROM was coming loose from the ECM and making it limp..check your PROM and make sure its in the ECM good..

heres what i did:

unplug the battery..open the ecm..take the prom out and re-set it nice and firm into its slots and see if it happens again..

what happens is..over time they just get loose and the piggy back tightens everything up..

this is the one i used

http://www.moates.net/g1-memory-adap....html?cPath=64

might be different cuz you have a 91 but im not sure..