Engines runs roughly, stalls, exept when accelerating

Mark,

If it has just started since replacing the cap/wires, I would try there first. Make sure you have the wires in the right order and that the cap is seated correctly.

I can only speak from experience on older VWs, but my 86 Golf acted like that and it was a bad o-ring on an injector leaking air into the cylinder. An easy check for this is to get a can of starting fluid and spray a REAL SHORT burst around the base of each injector individually, if the motor revs up, you have a bad seal. Be sure to only use a short burst. Too much starting fluid will cause damage.

It could be dirty injectors. Techron fuel injector cleaner works great. I would try some of that with a tank of premium if you don't want to physically remove and clean the injectors. Like I said, I don't know how the newer models are put together but it was pretty easy on my old one.

Good Luck!

Dave

By all means, check the easy stuff first. Plug wires on well? Coil wire? Rotor ok? Ground strap tight? Trying running a tank with Techron additive over at least a couple days to give the cleaner a chance to 'work'. (We're talking about from a bottle you pour in the tank, not just the stuff in the pump gas. Same chemical, but pouring in the bottle increases the concentration above what's in pump gas)

To me tho', it sounds like a vacuum leak since idle tends to show small ones more. The o-rings around the fuel injectors are just one point. Check all the hoses for cracks, or that they're there! Make sure they're routed properly. If it's a 2.0l, I got bit by the EGR hose back under the intake. My mechanic told me it's a common one for 'shade tree' guys to miss :( Don't know how the VR6's is, but it's prolly got a 'hidden hose' somewhere too.

If you haven't changed the cap & rotor, fuel filter, or spark plugs, might as well do 'em now. Oh, and don't forget the air filter. Once one of those plugs up it makes it run really badly too. All these buy the fuel filter is spec'd to get changed every 30kmiles anyway.

Mark '95 Jetta GLS, 2.0l

Thanks Mark, Lately it has been stalling a LOT when I come to a stop - otherwise the engine has been runnin ok. This has made me think that it is not due clogged injectors but perhaps electrical, seals, or clogged air filter. What do you think?

A few weeks ago I changed the cap and rotor but not the wires. I am thinking of changing the wires and plugs. One of the sparkplugs looks hard to get at - is it difficult to change them. Also, is changing th air filter and oil filter a big job?

Thanks!

Mark

The plugs are not that hard to change if you have a swivel type plug socket.

Like Mark said, try the easy stuff first. I would take of the throttle body hose and inspect that for cracks. This ribbed hose usually cracks and lets extra air in confusing and stalling the engine. I had to replace mine and that fixed my stalling problem.

Thanks everyone for the input.

I checked the air filter and saw that it was very dirty and had quite a bit of oil in it so I decided to replace it. (I put a cheap one in for now but may put a better one in later). When I took the old filter out I saw that there was remnants of a SQUIRREL nest IN the air filter compartment. I cleaned it out and it runs a lot better now!

Peter, Where is the throttle body hose? I should probably check that as well.

Thanks ! Mark

The moto club I'm in had a rat's nest in the airbox. Same kinda thing ;)

Some oil in the filter is normal. The PCV system on the 2.0l's was, well, not real effective in keeping oil from coming out the breather. Even the 'fix' (new breather/separator) doesn't seem to help much.

I think the hose is the BIG rubber one between the airbox and the intake manifold/throttle body. If you take the hose off to clean out the oil and look for cracking, check inside the throttle body for crud. Sometimes it carbons up and the throttle plates won't close properly, which causes idle problems too.

Just make sure to hook all the hoses back up when you're done. Including that plastic tube that plugs into the back lower part of the big hose where you can't see it. Can you say MASSIVE vacuum leak? Don't ask...

Mark '95 Jetta GLS

Sorry, I missed your other questions...

Changing the air filter is easy once you figure out how to hold your face right to get that @%!@#$ cover back on. But then, looks like you've already figured that out ;)

The hardest thing I found changing the plugs was getting the OEM wires off. They have shields that clip onto the plugs, and sometimes they're a real PITA to get off. After looking at the VR6 tools, I made one. If you do, careful to remove the burrs and still be careful not to nick the wires.

Food for thought, and literally YMMV, but even tho' the car is spec'd for 87 octane I found in a relatively unscientific test that the car got better fuel economy (3-5%) and ran better (my relatively un-carish spousal unit noticed the difference and I didn't tell her, ride with her or anything) with 89. She wondered what I'd done to the car! No difference with the 91+ stuff.

Oil filter is pretty simple. Just gotta have 3 elbows to get at it ;) Pretty normal actually.

Fuel filter isn't spec'd to ever be replaced, but I've been doing it every 45k-miles or so. But be careful. The hoses going into to it can be spendy to replace. Had to get my front hose/tube replaced. Expensive for just a stinkin' plastic tube with a hose crimped on the ends. Would just cut off the back hose and slipped on a new one, but didn't feel comfortable doing that without a barb on the end of the tube. Couldn't find any repair kits for this size tube either ;(

Sounds like you're making good progress. Good luck!

Mark '95 Jetta GLS

As mentioned in another response, it's the ribbed hose that goes from the throttle body to the MAF sensor. That should be cleaned and inspected for cracks. If it has a crack it will confuse the MAF and your engine will stall when you let off the gas and come to a stop.