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A2 GTI 1.8 8V Digifant PF Rough Idle and Acceleration Hesitation

The other day while I was waiting at a light an odd problem started: the idle speed was fine one second at about 800 rpm and the next second it started dipping down, trying to stall, then revving up to about 1500 rpm; it's acting very erratically. After a few moments it will rinse and repeat; it's acting very erratically. It is also running very rich by looking at the small poofs of black smoke coming from the exhaust. Also, if I try to accelerate heavily it hesitates and sputters. At first I thought I had a bad tank of gas that I had just bought the day before, but after two bottles of gas tank treatment (one last night and one this afternoon), the problem is the same as ever. The car has died a few times on me, always as I slow down at a light or stop sign and the rpms decrease.

New stuff recently: Plug wires Distributor Cap Distributor Rotor Oxygen Sensor All small Vacuum Hoses

Tried: Disconnected Oxygen Sensor- No change Replaced Crankcase Ventilation Hose- Maybe helped the idle some but not for the specific problem Replaced ECV Crankcase Grommet- Same Changed Coolant Temperature Sensor- No change

Anything else I can check? What's next? Idle Stabilizer Valve? Be advised that I have next to no tools with me at my current location- especially my multimeter. :( I may be forced to actually take it to a dealer. *Gasp*

Thanks as always for the help, Craig Smith Kaji Shun

Reply to
Kaji Shun
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check those ground wires at the intake manifold or the coolant pipe on the cylinder head. Those sometimes break and cause problems.

Also check the throttles and the throttle switches.

Could also be the Fuel Pressure Regulator and gas might be travelling through it's vacuum hose.

good luck.........especially without tools. :-) later, dave Reminder........ Before you criticize someone, you should walk a mile in their shoes. That way, when you criticize them, you are a mile away from them, and you have their shoes. Frieda Norris

Reply to
dave

I had a 90 GL with the 1.8 8V which came with similar problems. When I pulled the idle stabilizer valve, the hose underneath had a hal-inch hole hidden from view. Replacing the hose made it into a new car.

Pat Moore mailto: snipped-for-privacy@acsalaska.net

Reply to
Pat Moore

Also thoroughly check the accordian pleated hose after the air filter housing going to the throttle body. If it's got a tear it might only allow air through the side when the engine rocks a little, and so you may have to take it off to inspect it.

Bob

Reply to
Bob Hetzel

Did you check the plugs after you changed the CTS? I had some similar issues (still have some idle issues, but less of the erratic stuff now), and the CTS had failed, causing an extreme-rich condition. Then the plugs got fouled, so even after I changed the CTS things still weren't peachy. Cleaned the plugs (wire brush by hand) and things were a lot more copasetic.

The other suggestions are certainly good, but fouled plugs are pretty danged easy to check for and fix.

Reply to
Kevin T. Broderick

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