I posted this in the fuel forum but I haven't had much luck with help. Has anyone got any ideas to what might be the cause of my engine problem?

My car still has an issue on cold startups after being off for 5 hours or more.

I'll do my best to describe it.

She starts with no problem, sometimes may stutter and the revs go low and then rises and settles. I'll sit there and let her warm up for about a minute.
I put her in drive, she seems to take off ok but then the power drops away and for those seconds that it does, accelerator movement does nothing, just feels like it's flooding, and when I let it sort itself out the power comes on but much harder as if it's suddenly burning the extra fuel thats been dumped into the cylinders, kinda like spooling up and I have to take my foot off the pedal until it settles again, about 3 or 4 seconds.

The other day I tried something different, when she did it again, I kept the accelerator pedal still, not letting it out or pressing furthur, just kept my foot steady, and I could feel the engine power surging like a sine wave, the power went up a bit and went low, back and low, up and low.

Can this be a blocked injector causing a cylinder to drop out, or is it most likely ECU driver issues or actual fuel pump. Fuel pump is quiet?
There is an issue where the revs drop almost 200rpm when the air-con goes on, not diagnosed but probably the ECU.

The leads are fairly new, plugs are new, fuel filter is pretty new?

Other things to consider are a recently replaced intake gasket, where I tried to block 3 holes with gasket goo but a bit may have been sucked in as it wouldn't dry. But the gasket replaced now.

What do you guys think, I'm thinking about putting an XR6 ECU in my stock I6 Fairmont but am affraid of wasting money on dud fixes.

Cheers.
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Last edited by Kit on Mon Jul 04, 2005 12:39 pm, edited 3 times in total.

no vacum leaks? last time i had a vacum leak and i put the acel down it would just splutter and feel like its *flooding*

Yeah I've looked for them. After I did the intake gasket. Sprayed the cleaner spray around the vaccume areas, nothing...

check the map hose, sometimes they develop a small crack up the backside of them that can leak, and make sure t isnt leaking from where the booster pipe goes into the brake booster

What about the ISC?

Yeah the ISC, I've cleaned it so many times, I might have to see about replacing it.

Kit it is normal for the engine to drop 200revs or so when the aircon is tunred on due to the load on the engine, same as when u go from P into D

they should pick up again within a few secs

It does sound like some sort of fuel delivery problem.

Fuel filter ok?

Thanks guys. The filter should be ok, was doing it even with a new one.
Franky baby, when I put the air-con on the revs drop 200RPM, but they stay there. I can't understand why, at lights in drive with air-con is bad, the engine vibrates really badly, I have to put it in neutral at lights, because the f**k stays 200rpm under my set 750RPM, until I turn the air off again.. Could be the ECU for the air probelm yeah..?

This is a problem my car had before the distributor shat itself...

I also had a power problem and surging when I drove at low speed in 2nd gear thru town. The engine stalled on me a few times as well when I took my foot off the accelerator.

My end result for my car may be seperate from yours but I did have the same problem and couldn't find what was the cause.

Yeah it could even be a couple of things together. Like ECU and injectors, or ECU and Fuel pump (although mines quiet and never stalls). Does the ECU get to this point with bad drivers, can they cause all that?

Thing is with the fuel senario, sometimes the car suddenly comes good, and the power is beautiful and effortless. But it doesn't last long and for the rest of the time, 99%, it feels a little sluggish and has no real go at all, it's even sometimes like that feeling of being pulled back on each gear change when it's cool, it's just not interested in being effortless, more like breathless most of the time..

Does it feel sluggish all across the the revs or only up to 2500rpm? Mine was sluggish till 2500 (It barely had wheel spin in the wet) then it felt like a turbo had spooled up and accelerated.

Yeah this happens. Put the power button on and give it a boot, she's sluggish and breathless at lower revs, but it's like once it gets some air, it spools up and has a kick to it. In economy driving normally shes breathless or slack. But occasionally out of the blue, could be a week later, she comes good for 20 minutes and drives with what feels like more power and effortless delivery before reverting back to breathless.

I do have a K&N filter and XR snorkel on El intake tubing. Shes 160,000Km's old.
She's been like this for an age now, even with another ISC.

you'd thing there would be some codes on the system telling you what's going on. i think there is a guide to pulling codes of ef/l series falcons in the mods documents.
I guess tired old leads would do this. or some other breakdown in spark would do this.

Have you examined your spark plugs? What colour are they at the tips?

I'm also wondering whether a faulty tps or bad earth could cause surging in power delivery? With a K&N filter, could over-oiling eventually effect the MAP sensor? Bit short of answers, sorry.