Passat B5 1.8T rough acceleration after car warms up

[aussiebob]

Hi..My 1998 1.8T has developed a tendency after warming up to show poor accleration under load where it feels like it is going to stall. The idling moves up and domwn form 600 to 1000. I have cleand the TB and the problem is still there. It drives really well for the first 20 minutes and then the problem starts. the diagnostics show all OK

[aussiebob]

Hi..I thought i fixed the problem. I did a TB clean and MAF clean as well as the sparkplugs and the car drove as best as did for a long time..5 days without a problem and then it happened again. After driving 15 minutes the car was coughing under acceleration and wanted to stall. I stopped the car to make a phone call to my workshop to see if i can bring it in for them to observe and after 5 minutes I started the car and it drove OK...no problems for the next 20 minutes....would sensors be so fickle or is it the engine management unit changing the mixture to be running leaner? Could I have dodgey fuel as I noticed that i was starting to have this problem afer running a few tanks of E10 which is a 10% ethanol blend of around 95 octane.

Please someone help as I am out of answers and my mechanics cant help me out

[jenstersvw]

sounds similar to a problem i had. the computer in my care had to be completely reset at the dealership. another problem i had was intake valves not opening properly, cam sensors, and piston misfires. my car did stall on me once and ran fine the next day, but after the computer reset i haven't had a problem since. take it to the dealership and see what happens

[badluckbandit]

well ok u have an older car older cars ran on gas without ethonal ethonal is a alchol and has no lubrication so gas is a lubricant and alchohal is anti lube so some times ur valves will stick and not work right after switching to gas with ethonal in it try adding some kind of lube to ur gas i use marvins mystery oil in my 92 vw golf it was having the same type of prob and a little additive fixxed her up