Hi all, I have a 91 Golf GL, just passed 170k. I recently replaced the entire exhaust system, manifold on with the dual downpipe system. It was joy to drive afterwards. About a month or two after the replacement, however, she's developed a hesitation when accelerating from idle and what sounds like an exhaust leak. The major issue is the hesitation. The sound and the hesitation cropped up around the same time, I think.
I was under the hood this morning trying to find the leak. When I cranked the throttle the engine putters down for a second then revs up like it's supposed to. It's the same way when driving. I have to rev the engine for a second then I bring her into 1st, otherwise it's a brief almost embarrasing fight to keep her alive, then a sudden rocket off the line.
I don't think the o2 sensor is the problem. I replaced it about ~10-15k miles ago. There was a slight fight getting it off the old manifold, which may have involved some torch action. It is now located on the cat (She drove just fine for a month like this). I checked the wires and they look good, they run along the firewall so that they are out of the way
I was unsuccessful at finding the leak. I'm going to the store to get a hose for some better listening. I put my hand around the manifold/ downpipe junction and did not feel any puffs, only slight wisps coming from the dp/cat junction.
Any ideas as to the cause of the leak/hesitation?
thanks, Matt