I've had a couple of threads on this one but starting a fresh one.

4-6 weeks ago, my D2 (2004 HSE, 190K, rebuilt at 125K due to slipped sleeve) started to act up.

It would lose power (like it was in a limp-home kind of mode), maybe die, but then eventually start, and after sitting for a while (2-48+ hours), it would run fine.

Then one day, it died. Not exactly died died, as it will start for a second or two, will rev up to 2-2,500rpm, then drop to a struggling couple hundred rpm with a couple of odd detonations (kind of like backfires, but not exactly, more like a burp or indigestion) before dying.

Initially felt like a fuel issue to me, but checked the pressure at the schraeder on the fuel rail and it read a full 50psi. Likewise, checked spark using an inline tester on the 3 cylinder (I damaged cylinder 3 ignition wire connector at the coil pack -- they've been relocated from the back of the engine, so I have custom wires) and there's spark.

Read on forum that these symptoms were typical of a CPS failing, so replaced the CPS with a new genuine Bosch unit (believe it was the original CPS in there, so 190K miles on it, what a PITA, my harness connector seems exceptionally short, and no one has explained on this forum exactly how the connector works: how it is secured in the bracket and then how you separate it -- I am going to write up something about this).

Engine is behaving exactly the same as before the CPS replacement: starting and revving momentarily, then struggling, a few unusual detonations and dying, all within a few seconds.

Two codes on the OBDII: the MAF 0102 (MAF also replaced with a Bosch unit)), and P1884 (Engine coolant level lamp short to ground).

I have new coil packs and will swap them out (having been relocated, it's now a 20 min job). Believe they are the Bosch Coil packs with 190k miles on them.

Read the a similar recent thread about a fuse box issue, but that seemed to be a dry hole.

Any thoughts out there of what might be going on?

 

A little more info.

To get it to run for a few seconds requires feathering the accelerator.

Could a throttle position sensor cause this kind of problem?

 

Can you try a new/ different MAF ?

Or a code reader that would graph your input sittings so you can tell.

I’ve had a scenario where I had checked air filter & didnt properly latch MAF to intake - it dislodged while on a ride & exhibited similar struggle and engine cut out.

 

It has a new Bosch MAF. But I swapped in an old, kind of working MAF anyway just to test (non-Bosch cheapo I bought at the time of the rebuild and which lasted about 6 months before it started throwing codes; I replaced the cheapo with a Bosch 5-6 years ago but kept for some reason kept the old cheapo), and no change in the behavior -- it'll start, run 1-3 secs up to 2,500rpm before dropping to 250-500rpm for a few more seconds while burping (weak, muffled backfires) a couple of times and dying.

Also, someone on the forum said that the engine will run even with the MAF disconnected, so I right now I don't think that my new Bosch MAF is defective out-of-the-box.

Some folks on a different thread think it might be catastrophically clogged cats, but could the cats really clog that quickly such that one minute it is running and five minutes and five miles later it refuses to do anything more than the 5 second sequence I described?

I've got new coil packs, will replace those today (easy peasy job since I relocated the packs to the front of the engine compartment).

Could one pack be good and the other bad, resulting in the motor running for 3-5 seconds on 4 cylinders before dying? I have only confirmed spark on cylinder 3 because I had that wire off to repair an ignition wire terminal/connector on the coil end (because of the relocation of the coil packs, I need custom wires).

If the coil packs don't fix it (they have 190K miles on them as well, so good time to do a pre-emptive servicing anyhow), I am going to spray some starter fluid in to confirm I don't have a fuel delivery issue. Any thoughts about where I should spray the starter fluid in? on the manifold? FYI, regarding my intake manifold, I have also done the PCV valve modification that has been recommended elsewhere on this forum.



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Clogged Cats would typically restrict flow at high power but not be noticeable at lower power settings.