98' Disco Engine Mis-Fire

[CrappieCruncher]

I have a 98' Disco that is mis-firing sometimes while driving. I reviewed some older posts and it seeemed like it might be the VSS. So the last time it happened I tried shifting into a lower gear to see if it would still do it. It still misses when I slow down and go to a lower gear. So does that elliminate the VSS as the culpret?

I also removed and cleaned the TPS and IAC. this appeared to help for awhile but it is doing it again.

Also at times when this happens (it has been going on off and on for over a year) the check engine light will come on and read "engine misfire" on the printout.

What could this be? Should I replace the TPS & IAC? Or could it be a bad fuel pump? Does the fuel pump go out all at once or a little at a time?

I Changed out the plugs and wires a year or so ago.

 

[joey]

This could also be the MAF sensor, or you may be experiencing some corrosion issues in you ECU or a loose pin in one of the cables going to the ECU.

 

[CrappieCruncher]

I am guessing that a MAF is a mass air flow sensor. How would I go about checking these things? And can you give me an idea of where the MAF is and Where the ECU is and I think I can check for loose pins, etc.

Thanks for your input.

I take it you don't recommend replacing the TPS or IAC.

 

[joey]

Normally for what you are saying the TPS and IAC is not the issue, when they do go bad and don't just require a cleaning it will stall at idle.

MAF (Mass Air Flow) is located just after the air box in the air intake hose. Unplug the connector, remove from the air intake and clean (spray it out) with a can of MAF cleaner.

ECU is located on the passenger side rear fender area behind the fuse box and closest to the firewall, it will have a plastic cover on it and 4 plugs.

 

[CrappieCruncher]

Joey you are the man

The codes on this issue are as follows.

P-0307 cylinder 7 mis-fire.
P-1316 Manufacturer Control Ignition System.

I replaced the cylinder 7 spark plug. I had just replaced all the plugs and wires about a year ago.

Do these codes make you think I should replace any components?

Rhino Herder.

I ran SeaFoam through the crankcase and the fuel system also.

I can't get anybody to answer a question about seafoam. when you put it in the crank case how long should you leave it in there before changing the oil? The can doesn't really say anything about it. But A friend of mine who is a mechanic said not to leave it in there any more than 50 miles or so. What do you think about this?

Thanks JOEY!!!!!!

 

[joey]

Seafoam in the crank case, not longer than 100 miles in my opinion. And if I recall correctly that is what Seafoam told me when I called them a couple years ago.

As far as you codes. Could be a bad Wire as well, what type of plugs and wires are you using?

 

[CrappieCruncher]

bosch platinum plugs. I don't recall the brand name on the wires. they were the high end variety.

Anything on the codes?

 

[joey]

May or may not fix your issue, but get rid of the bosch platinum plugs... they don't work well on a D1. Buy plain old cheap champion plugs.

This may fix the code issues..

 

[CrappieCruncher]

Mis-Fire is Gone!

The mis-fire is gone. I checked my spark plugs and 5 of them were loose!! I don't get it why, I torqued them when I put them in. Any way I replaced them with the champion cheapees and cleaned the MAF and it is running like never before. Thanks to all for the Elp!!