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CSR / Duratec 2.3: Intermittent engine 'cough' under load

​Hi, can anyone help with this ...
My 7 is a standard CSR 260 with the Duratec 2.3 and MBE992B ECU.

​Under full acceleration I get a very occasional 'cough' or 'hesitation' from the engine.  It doesn't really feel like a misfire on single cylinder, more like a short loss of power across all 4 for perhaps half a second.

Other than this annoyance, it runs fine.  It's been on a rolling road for setup / remap with 2 Steves and no issues with the power.

It's done this for the 3yrs I've had the car, but as it's been a rare occurrence, I've adopted a 'wait and see' approach.  It now seems to be getting slowly worse, so I probably need to find out what it is before I get stranded ...

My hunch is that it's fuel related, given that it seems to be hitting all cylinders at the same time (but can't be sure about that either).

A few things I've tried:
- replacing the fuel filter
- cleaning various connectors including water sender, ECU and MFR (mentioned in other posts)
- I only run it on V-Power

Any suggestions very welcome.
tks, Andrew.

Might be a coil pack going out. On my R400D I had a small hiccup in acceleration especially at mid revs and mid throttle, felt almost like turbo lag, just annoying to begin with a year or so ago. The past couple of months it has quickly worsened to the point that the car would sometimes misfire on light throttle after hard acceleration. Checking the plugs would never show any variation between cylinders, they all looked perfect. Also checked and wiggled all wiring in the ignition, TPS, CPS and other sensors with no effect. Once it became repeatable and started to do it at idle, I put an infrared thermometer on the primary exhaust pipes and found that #1 cylinder would cool rapidly while it was misfiring. I swapped the coil pack on #1 and the problem has disappeared.

Thanks for that aerobod.  Definitely worth a try.  I just bought a set of four used coil packs to experiment with as swap outs.  I also checked cleaned all the loom connections under the coil pack cover though they all looked fine).

Current: CSR 260 | Silver / Matt Black Stripe
Previous: Roadsport SV 165bhp VVC | Yellow / Green Stripe

I had a similar experience on my R400D.  The cure (like aerobod's) was a new coil-on-plug (COP) for #1 cylinder.

Another possibility is damaged/fractured COP wiring.  Does the 260 come  with the flexi-loom as standard?  If not, have a thorough check of the COP wiring inside the connector (pull the pins out for the best results).


I just received a set of new coils today, I had a spare of the old ones, but the old part seems to have been superseded, so I thought I would put in the new part number across the board, assuming overall enhancement (perhaps a bit of a stretch) as the part has evolved. $38CDN (£23) each for the Ford / Motorcraft part. Original part number was 4M5G-12A366-BC, new one is 4M5Z-12029B (DG541).