engine cuts out only when moving

[turbovan89]

Ok, this is a weird one that really has me stumped. I have an 89 mini 2.5, T3/T4, intercooled 5-spd that ran beautifully. A while ago it would hesitate while at cruising speed. Not often (once every few miles) and only for milliseconds. After a couple of weeks of that it started to gradually do it more often, like every few seconds. Now it does it constantly, it is like riding a bucking bronco! The really weird part is that when sitting still it runs great (at idle and revving the engine) but the instant you try to move it starts cutting out and bucking like crazy. I have checked my grounds and they all appear to be OK. This one is driving me crazy. Has anyone else encountered anything like this. I have a G-casting head, FWD stage 5 cal and +40s to put on but I would like work this problem out first. Also battery was drained due to dome light left on so there are no fault codes other than 12.

Thanks in advance for any help,

Deric

[Turbodave]

Have you checked your fuel pressure? When the filter was clogged up in my van it acted similar to what you described, idles fine and revs up ok in neutral, but when you put a load on it and the fuel demand increases it runs like junk. A dying fuel pump can act the same way.

Other items to look at may be the hall effect plate or it's wiring, and the Map sensor.

[turbovan89]

Thanks, I'll check those out tommorrow. You're the second person to suggest the HEP so I'll start there. Also I replaced the fuel pump last summer with a Autozone piece so that might be suspect also. I have a stage 5 cal and +40's ready to go in but I want to work this problem out first. I know I will need to upgrade the fuel pump at that time, any suggestions as to the best to get.

Thanx again,

Deric

[Turbodave]

The 255l/hr Walbro pumps have a good reputation and are reasonably priced.

[PUNKSLIP]

I have had 2 cars give similar problems and it turned out to be the plug wires. Don't race out and buy a set, but don't rule then out.

John

[GLHSKEN]

I'm leaning towards a fuel pump issue as well.