Hi everyone.
I always love this forum, and love to share all experiences with all Disco lovers from All over the world. I have never had major issues on my long time lover- Discovery, but it's been hating on me for a couple of month. I really need somebody's help!

1997 Discovery SD V8 4.0 Automatic, 138.xxx miles.

It started misfiring when the motor gets warm, especially around 1500 to 2000 RPM, it goes up to that RPM with no hesitation, but as soon as gets to around 1500 RPM, starts feels like losing power, and almost no torque. Up hill is worst. Lately, here in Seattle is over 75 degrees everyday, and now it doesn't matter if it's cold or not. It runs sucks as soon as I start engine.

I don't know what to start. I changed plug wire, plugs, cleaned throttle body, checked all vacuum. Haven't done induction clean yet.

And more! one of my friend told me change the TPS sensor, I did, and now RPM is around 1300 all the time! I just did like 10 min ago, Now I started freaking out.

Fuel temp sensor?
Crank position sensor?
Crank shaft sensor?
or even worse?

I need some words and advice before I mess up my old friend Disco. I wanna keep this as long as I can.

Thanks in advance.

 

Codes??

 

I got 1179, 1177,0300,0301,1316 and 1313. These codes are when it's hot. Haven't check the code when it's cold.

Thanks.

 

Put your old TPS back in. They have to be set by the dealer, or someone with a scanner. Hopefully it will still read your old one.

Have you changed the fuel filter? Have you checked fuel pressure at the rail?

What kind of plugs and wires did you use?

 

Maybe a bad plug or wire Id go back and check all that out.

 

I replaced my TPS not long ago and when I bought it from the dealer he told me it didn't need to be reset... only the stepper motor needs to be reprogrammed. Miine still idles normally. If his idle jumped up then maybe he didn't tighten down the screws on the TPS or has a vacuum leak.

 

goes both ways. with both parts.

 

You have a bad VSS, vehicle speed sensor, it cuts spark to control road speed, it is a speed limiter and when they go bad they do very weird things.
It is a bout a $40 part and you can replace it yourself.
www.discoweb.org has a write up on this in their tech section.

As for the high idle, rent or buy a scanner that reads live engine data including engine rpm.
Loosen the screws that hold your TPS in place one turn each, then with the engine hot and using the scanner for RPM and NOT the tach tap the TPS with the handle of your screw driver to set the RPM to around 600 with no load, that means no lights on and no A/C on.
Set it below 550 and the engine will stall, set it to high and you waste gas as well as put strain on the diveline when you put it in gear.
This is the Red Green fix, the proper fix is to have the idle set by the dealer.

 

Dude, Spike, where do you get off man? What did he say that led you to that? He said nothing about road speed, just RPM's. A clogged fuel filter will cause the engine to cut out the same, and it is a five minute, $10 job.

I don't mean to be an ***, but there is no way to diagnose it to a VSS with the info given. You have a ton of posts on here, so people think you know what you are talking about. Stop being so damn absolute with your responses, or you are going to cost people time and money!

 

That tell me he is driving when this happens.
I take no offense to you OKDGuy, I admit that sometimes I do jump to conlusions but he has tried everything else.