Hi All,

I have a 98 Discovery and I've posted here before about the brakes. I was waiting for a master cylinder so I'd not run the vehicle for a couple days. I went out today to give it a go and it idled horribly. When I first bought the truck it would not stay on until it warmed. Then it would idle OK. It has gotten progressively worse. Before I give up I would like to have some input. The check engine light flashed for about 1 minute and then stayed solid. Im getting P1314 and P1193 fault codes. I believe these are for the passenger side 02 sensors and Cats. My question is. Would a bad cat and sensor cause such a rough idle or is a misfire causing these items to fail. The vehicle passed emissions 4 months ago. Thanks.

 

By any chance is your IAC (stepper motor) unplugged or have you bypassed it as I did?

It increases airflow around your throttle body on startup.

If it's plugged, or dirty, it will cause poor idle until warm.
That, in turn can foul your o2's (tho' I think a good 20 mi highway run would clean them up) could also throw misfire codes.

If you've never cleaned it, search "cleaning stepper motor" you'll find some cool stuff

DO NOT MESS WITH THE SHAFT, clean with toothbrush & inside throttlebody housing, too ( I used wd40)

 

The 02 issue is for the heater portion of the 02's and should only be an issue when the engine is cold, makes since. A failed cat will cause back pressure, it needs to go as well as finding out what killed it and repairing that also.
What year, model and mileage and what has been done tune wise to your engine in the lat 30,000 miles?

 

I just bought the car a few weeks ago. It has 200k. It ran ok when I bought it. Still had the issue of cutting off when warn. Had no problem when I was giving it gas. Now after sitting, it runs even worse when I give it gas. Had new plugs and wires before I bought it. I just dont know what to do here.
Where should I start. 1998 Disco 1

 

Your first post said it wouldn't run right until warm, this post says it won't run right after it's warm


luck,greg

 

Sorry for the poor post. Initially it would only stay on when warm. Now it has bad idle and dies when I give it gas. Im going to change the fuel filter tommorow and maybe test fuel pressure. Does that sound like a good first step?

 

Tried to change the filter but the connections are rusted on. Won't budge. The filter mount has also rusted away so the filter is just dangling. Does anyone know the size of the metal brake line? Are they the metric equivalent of 3/8?