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Alright well i picked up an mk111 7mge for 1000$ a couple weeks back and when its running it runs good, but it has a really unreliable start. i changed the oil and oil filter, put in ngk sparks and wires, changed the igniter and coil pack and switched to premium gas, and ran techron through it, The car seems to be carbon fouling, also sometimes it will start cold but it seems to hate starting hot, if it stalls or if you turn it on it wont start back up, its a rebuilt engine with only around 1500 miles on it. i ordered a new fuel filter which im waiting on now because it had been sitting for a while, but idk what the problem could be, can anyone help?

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probably killing it with your premium gass. you don't need to run it. Once in awhile won't hurt.. but your actually doing more harm then good.
first thing to check when buying a car is any stored codes? do a dio.

aye.

freind had a friggin mazda that did this too me once. we replaced the plugs and wires, fuel filter, and it still did it. we were baffled, cuz it would run just fine. then it quit altogether. we took it too a shop and had it diagnosed.

it was the damn o2 sensor....that didnt make sense to me, but we replaced it and it still drives to this day.... darn ford...:rolleyes2

i read that this car ran better off premium and people ran 96 all the time premium around here is only 93, and yeah the o2 sensor is blocked off on this car i ordered a new one but i cant even find out where the wire is in the harnes to connect it because i was going to extend it

far as i know all mk3's should have an o2 sensor...

yeah i know they all should, but the person before me changed out the stock headers and downpipe which relocated the o2 spot to right before the cat, but he blocked off the o2 slot will like some steel sheet, and then he might have cut the wire

I also have an aftermarket header with the o2 sensor in the same location which causes a CEL. Now I don't know if that is your problem but I am going to move the sensor on mine up so it is much closer to the stock location. It seems that just extending the wire can cause problems as well as the temp drop because of the lower location down the pipe.

if the o2 sensor is not close enough to the collector or too far down stream, it will not get hot enough and your car will not run properly.

an option would be to get a heated o2 sensor. then it gets to operating temp quicker. but ive also had them falsify readings when placed too far down the exhaust. the car ran fine, but poor mileage ensued.

yeah true, but the car isnt running an 02 sensor at all which i think is my problem, it looks like he cut the wire on the wiring harness or i just cant find it, im prob going to try to but the oem headers and down pipe and just do custom pipe after the down pipe

id say thats definitely your problem.

yeah it just sucks cause now i dont know where the damn connection is ive looked on numerous occasions

i believe theres a pinout on the TSRM, find what color the wire is on there and trace it from the ecu itself. it should come out the end of the harness after it loops all the way around the drivers side. i believe it clipped to the firewall originally. it may have been clipped off at the end so check around where the harness crosses over the cam gear housing.

if you find it, you can keep your header and drill a new hole where the collectors merge, then have a bung welded on for a decent price (or a buddy with a welder), then put a heated o2 sensor in. problem solved and you get to keep your header.

The O2 sensor connector exits the harness right by the oil pressure and temp sensor wiring.

keep running 93 octane in your car all the time. you will have to replace that shiny new 02 sensor after awhile. but hell don't take my word for it =) do it and find out.

i never said i was running it all the time.... i havent even had the car for long, and i was just running it because i heard it was good for it. i never said i wasnt going to take your word for it. and also its not running an 02 sensor like i had said, which is one of my many problems

honda idleing today when i started it, jumping from 500-1000

yea i said that "NEW o2 sensor.." implying the one your putting in. good luck man.

ahhh alright. Thanks