Clean Throttle Body.

[Redsteve]

Hello all, I hope you are enjoying the great weather that we seem to be having at the moment. B)

I thought I would take advantage of the lack of snow, rain and wind to get a few jobs done on the old LS (MK IV 2000).

I replaced a blown sidelight bulb, tidied up the boot seal where I had recently repaired it, took off the number plate light covers and gave them a good clean and cleaned the throttle body.

When I went to restart the car it was ticking over at about 2000 RPM when cold, way higher than normal. I thought it might have something to do with the carb cleaner I had sprayed into the throttle body so I left it ticking over until it was warmed up. At normal operating temp it is still ticking over way too fast, about 1100 RPM instead of the 700 RPM I am used to.

I remembered reading on this very site that when people had cleaned the throttle body they then had to adjust the throttle position sensor to get the car running sweetly again. Armed with my screwdriver I confidently strutted round to the nearside of the car to make said adjustment only to find that someone had been there before me with a badly fitting screwdriver and chewed the heads off the screws. There is no way I can get the damn screws undone while the TPS is attached to the car.

I am seriously hacked off that I am now going to have to spend tomorrow stripping down the throttle body and removing it just so I can get to two little screws to cut slots into the heads instead of spending the day with my wife. :tsktsk:

Rant over, thanks for listening.

Steve.

[91LS400vgb]

I faced a similar issue and was able to unscrew them using a needle nose vise grip pliers.

[ROYT]

Check for air leaks first....

[ColinBarber]

drive the vehicle and then let the engine idle in Park. Repeat a few times and the idle speed should come back down. It does take it a while to readjust sometimes. You shouldn't have to alter the TPS if it was set correctly in the first place.

[Redsteve]

drive the vehicle and then let the engine idle in Park. Repeat a few times and the idle speed should come back down. It does take it a while to readjust sometimes. You shouldn't have to alter the TPS if it was set correctly in the first place.

Thanks for all the advice Guys.

When I got round to stripping the Throttle Body Sensor off the car the next day and cutting slots into the heads of the screws I was well pleased with my efforts. I put it all back together again and got ready to make the adjustment, I had loosened the screws so I could twist the TPS to slow down the tickover. When I had got it running nicely I tightened the screws, which just pulled the TPS back to where it was before I started and the engine revs shot up again! I must have tried this about 20 times and was getting very frustrated as my wife and I had to go out in the car later that day.

Anyway, time marched on and I couldn't get it to tick over at the right speed before we needed to go out so I just tightened up the TPS screws and left it.

However, just as you said, after driving the car for a while and leaving it in Park at traffic lights and such the revs sorted themselves out and it now ticks over quite happily at about 700 RPM.

I love cars that fix themselves, I just wish I had known it was going to fix itself before I spent hours working on it.

Steve.