Thread: Low throttle surging

Ive had this problem for ages, thought it was just my dodgy old engine mounts, but have prothanes now and its just as bad. Its terrible to drive at low throttle, so light cruise and also when trying to drive slowly in 1st or 2nd like in stop start traffic i have to dip the clutch all the time.

Ive checked the tps, and tried a few different settings, and sometimes it goes away, but then usually after a good hard drive it comes back with vengance and is undrivable.

Its a p10 ecu with DB on a p12 20v engine.

Any ideas of other things to look at would be appriciated.

My car would sometimes do that on the initial warm up. I would depress the clutch and give just a tad bit of gas and I would have that issue. It has done this on my original de and my ve. Your throttle cable might need some slack in it to avoid this.

When it's cold, can you rev past 3k rpm? Also does your check engine light come on?

My car also does this and has done it since i installed the jwt ecu 6 plus years ago. I just thought that it was something with JWT ecu and had to live with it. It did it on my de-t and now on my ve-t to a lesser degree, but still there. Maybe too lean?

I have tried fuel pressure and tps settings only to make things worse from what the stock settings are supposed to be.

Have you tested your maf? Also what about your o2 sensor?

I think its an issue with the TPS as opposed to anything else. Its got a 70mm 20v stock TB, and at low speed it only takes a very small amount of throttle to keep it moving at a constant speed, so the problem is when you i back off a little it goes into fuel cut/overrun, then touch the pedal again and it gos back on fuel again. Ive adjusted the TPS to .55 volts and its a lot better, this makes the overun part of the throttle very short, i might even try .6 to .65 and see if it gets better still as long as it still goes onto overrun when fully off the gas.

Ive also made a new throttle actuator with a offset, so the cable is further from the shaft at low perdal making it softer, and then closer and more responsive at more pedal.

I think there may be some value in looking at the mixtures on the ecu at this point, but i rely on someone else to do the tuning.

my daily car does this at low rpm/throttle... but it was randomly one day. If I coast in first its like a bull ride. I'll have to check my tps when I get a chance.