Fuel Starvation?

July 25, 2003

Hello all, I need your help....... I have recently bought a 91 Celica GT which has an intermittent fault, when I've been driving and come to a stand still ( Traffic lights or at a junction ) and set off again the car " coughs and splutters" for a few seconds before clearing and then runs OK after that. It is intermittent and ther doesn't appear to be any pattern or conditions that this happens under. Does anyone know what this could be? I'm hoping it's not the fuel pump!

Cheers

Pob

August 2, 2003

I seem to have the same problem on the same model/year car. Unfortunately, I also haven't got an answer yet, but I thought my experiences may help. My misfiring problems started a couple of years ago. I took the HT leads off and found oil in one of the spark plug wells! I cleaned it out, tightened the cam cover bolts and everything seemed fine for a couple of years. A few weeks ago the car started misfiring again. As the car was due for a service, I got my Toyota dealer to have a look at it. They told me it was due to oil in a spark plug well, which didn't surprise me. They cleaned out the oil and again everything seemed fine for a couple of weeks, when it started misfiring again. I checked for oil and there was none there, so I got my Toyota dealer to look at it again. They said they couldn't get it to misfire, but they checked the HT leads and spark plugs and said they all looked fine. It does seem now as if the oil problem must have just been a coincidence! Mine starts to misfire after it has been driven for a while and it usually seems to need you to stop and start a few times before it will start doing it. Actually turning the engine off and back on before the engine fully cools down seems to aggravate the problem. The severity of the problem varies over time. It can stop doing it completely for a number of days and then it will start again. As with yours, mine does it when you drive off again after slowing down/stopping at a junction. It seems worse if you slow quickly. It never does it until you have been driving for some time. It feels to me like some kind of fuel starvation problem. If it wasn't injected, I would suspect some kind of vapour lock. I don't know if this helps, but maybe it will enable someone out there to diagnose the problem. Looking through other posts on the site, some people have suggested the fuel pump could be the cause of similar sounding problems. They have also suggested timing and the "oxygen/lambda sensor". I wonder if the ECU could be to blame.

August 3, 2003

Had same problem with a MR2 SW20 - change the plug leads. The leads break down with heat and age. Seems ok when engine is cold, but as soon as it heats up it starts to misfire. Low rpm or during acceleration are worse - okay when you take your foot off the throttle.