Is this an overfueling problem?

[Guest Rottweiler]

Recently I`ve had problems with my Supra. I had a diagnostic check done about a fortnight ago and it came up no fault codes stored. I`ve changed the plugs, distributor cap, plug leads and rotor arm for new ones. One rocker cover gasket was leaking oil into the plug holes so both were changed. I hoped the problem was cured as it seemed to drive fine until today. I had only gone about 4 miles when it started to pull back and seemed to be missing. I had to keep revving to prevent it from cutting out.I started with a quarter of a tank of petrol and its now nearly on empty. When I got the car home it stopped on me outside the house. It started again straight away but it was revving at 2000 revs on tickover, then dropped back to 400 then back up to 2000 without me touching the throttle pedal.After parking I looked around the back and the valance and exhaust pipe are caked in soot.

Does anybody have any ideas as I dont know what to do next. I wish there was a fault stored as then I`d have some idea what I was looking for.

[bondango]

Could be a few things causing your problem as the ECU dosnt log some sensor faults.

I would check all the Vac lines, especially to the map sensor, also check for any vac leaks, Check Throttle position sensor, Map sensor, Idle control valve (inspect and clean), Oxygen sensors, ecu coolant temp sensor. Youve checked and replaced the basics on an N/a, you should be able to hunt the problem down easy enough

[pistonbroke]

I'd start with the idle speed control valve.

[Guest Rottweiler]

Many thanks, I`ll try what`s been suggested and keep my fingers crossed `cos at the moment it seems as if I`m just throwing money at the car for no reason.