another interesting problem

[Dubbs]

I've had that happen to me before. It turned out to be cracked headers. They cracked where they split from 4 to one pipe. I had to look pretty hard, because they were small cracks. I'm not saying it's your problem, but at least it's another idea.

 

[widepud]

would a loose bolt on the header also maybe cause that? because i have a loose bolt on the header,just been busy with other problems and havent tightened it.

 

[joey]

If it is leaking/sucking enough air this can cause issues.

 

[Dubbs]

Like Joey said. If it's not sealed, it could be causing issues. I'd tighten the bolt and see what happens. If it's that easy, than great.
I found out mine was bad at about 75 mph on a highway. Out of nowhere the engine bogged down, it got really loud and almost seemed like it shifted into a lower gear. I couldn't get up over 55mph. After I had my headers replaced my car ran perfect.

Good luck!

 

[wolf]

new cats and o2 sensors didnt fix this problem

There is another infamous Disco issue that may be popping-up on you and that is the sticking-valve syndrome! I have had it happen (tends to happen in warmer weather or when vehicle has been running a while at highway speed) - its very much like how you have described it - only I call it 'engine-feathering' -loss of power like its in some sort of crappy downshift or something and then it picks right up again (it can fool you into thinking a fuel line blockage or dirty fuel-filter issue).

According to the Rover V8 experts out of the UK, RPI (not RIP [lol]), the cause of this issue is low-octane fuel in that the fuel mapping is weak in mid-range RPM's when you use our regular gasoline (remember, Brit hi-test begins at 95 [our 87 Octane is bottom of the barrel by Brit standards - in other words pure crap - so try not to go lower than 91 Octane if you can help it]) - this weakness causes a substantial increase in the engine's internal heat which can lead to blown head-gaskets, slipped cylinder liners and, yes, sticking exhaust valves.

Believe it or not, there are ways of fixing this without doing a valve job (that's if your compression check tells you everything is more or less A-ok) and it can start with a Seafoam Treatment (but I would not count on that as most of it burns off before it could even touch your exhaust valves), better still, you can try the Xado Engine Treatment (its also great on worn gun barrels) and be patient on that as it may take two treatments (@ $100.00 approx per treatment its not cheap). It will make your engine run smoother - that is for certain, the science is real - its not snake-oil, and it may make its way to your potentially damaged valve.

How do I know this? I tried it and my seriously clacking valve (which was also showing a dip in compression values [I had shared this info with Joey earlier]) finally shut-up!

Was I lucky? Probably - but if this is your issue its worth a shot and the rest of your engine will not complain either - even if the problem turns out to be something else or, ultimately, you still have to do a valve job (ouch!).

Wolf

 

[widepud]

update. the problem is getting worse and very annoying. just checked the fule presure to the engine its good. even watched the guage not move while the engine did its failing or what ever it should called. also tryed unplugging sensors. one at a time. the mass air sensor, idle controle sensor,and two others i dont recall the name of and still had the same results.also replaced a coil in the coil pack that was reading less than it should. like i mentioned before its got brand new plugs and wires. any other ideas?

 

[greg409]

update. the problem is getting worse and very annoying. just checked the fule presure to the engine its good. even watched the guage not move while the engine did its failing or what ever it should called. also tryed unplugging sensors. one at a time. the mass air sensor, idle controle sensor,and two others i dont recall the name of and still had the same results.also replaced a coil in the coil pack that was reading less than it should. like i mentioned before its got brand new plugs and wires. any other ideas?

I've been watching the progress of this & wonder:

When you checked fuel pressure were you driving, you say it died while you drive or just sitting @ idle? (should be above 37lbs. always.

I'd try driving it with the gas cap loose, to me your symptoms sound fuel related since you stated if you let off the gas it will clear, leading me to believe it's not ignition.

luck,greg

 

[joey]

This could also be a ground issue at the ECU. Check the plugs for corrosion and make sure they are clean and happy.

 

[widepud]

the fuel pressure gauge was being rerad while driving. it stayed right around 35 and didnt drop even when the issue happend. also,letting off the gas dosnt clear it any more. what it will dois be driving full power(at whatever giver speed) it now happens at any speed. and say youre just driving along at 60 w your foot on the gas to stay at 60,it will cut out like this for maybe a second,then back to full power for about 2 seconds,then cut out for another second,then back to power,and so on and so on and will keep doing it. although sometimes after having done it for a while it will clear up and drive for like 15 miles before it does it again. ill try the gas cap and look over the ecu. any new ideas given the new info? also it dosnt always have to be running at full temp for the issue to happen.?

 

[joey]

ECU grounding issue... I have heard of this before.