[SlowSilver]

My 2000 Insight with 326,000 miles has developed a new issue over the last few weeks. This started out as a sudden decrease in milage from 43-44 MPG (60 percent city/delivery, 40 percent highway/commute), down to 36-37 mpg. The car was doing the herky jerky thing between 2,000-3,500 RPM from time to time.

I assumed that it might be dirty fuel injectors, and put in a bottle of Techron fuel system treatment. That didn't fix the issue. The car then developed a very noticeable hissing/sucking noise from the engine that intensifies/gets louder with RPM. I tried changing out the intake manifold gaskets. That didn't fix the issue either. The EGR plate wasn't dirty (frequent cause of the herky jerky condition). The EGR gasket was not replaced, but looked ok to me.

I did increase my MPG to around 40 after the intake manifold gasket replacement. The old ones did seem to be fine however.

The car pretty recently had the coil packs and spark plugs replaced, as well as a valve adjustment. The battery packs are pretty much non-functional at this point, and mostly used for starting the car. I grid charge it every night, and pull a fuse to reset the system once or twice a week. It doesn't have an IMA light happening with this routine. I might get a few seconds of assist shortly after the system reset.

I have heard of the method of finding leaks with a propane torch or starter fluid. This makes me a little nervous, and I was wondering if any of you have had this issue, and what the solution/fix for this was.

Any help would be much appreciated.

 

[*sean*]

When was the EGR valve last replaced?

(unrelated, then again maybe it is in some way):

The hissing you are describing - does it get louder when you demanding more power? Such as when you are out on the highway and trying to go up a hill? Do you have to hang out at a very high RPM and low gear to make it up grades that were easier to climb before? Can you hear it then?

 

[SlowSilver]

The EGR was changed out only a year or so ago. The PCV valve the one that goes on top of the engine is a bit dirty and clogged. My car is a manual and I do have to let it rev up a bit on hills. By 4,000 RPMs the hissing sound is getting pretty loud. It is barely noticeable below 2,000 though.

The car definitely feels a bit down on power, not that it had a lot in the first place. I'd say it feels like it's down maybe 15-20% power wise.

 

[Gasoline Fumes]

If it idles normally, it's probably not a vacuum leak. I'd look at the intake tube between the air filter and throttle body. Any cracks? Is the intake temp sensor in place?

Exhaust leak? Have someone cover the tailpipe while you listen. Any leak will become much more obvious.

 

[*sean*]

If you have a melted/plugged catalytic converter the backpressure would increase with RPM and potentially blow past the flexible joint or other places, making the hissing sound. It would drop your power significantly.

Here is a video that shows how to use a vacuum gauge to check for a restricted exhaust pipe. You can find a vacuum tester at Harbor Freight or possibly rent one at an auto parts store.

Using a Vacuum Gauge to Find Exhaust Restrictions | EricTheCarGuy

As long as we’re on the topic of engine mechanicals, let’s talk about the effects of a restricted exhaust. Imagine being able to breathe in but not out. It wouldn’t be long before you pass out cold.

www.ericthecarguy.com

Let us know how it goes.

 

[SlowSilver]

If it idles normally, it's probably not a vacuum leak. I'd look at the intake tube between the air filter and throttle body. Any cracks? Is the intake temp sensor in place?

Exhaust leak? Have someone cover the tailpipe while you listen. Any leak will become much more obvious.

The idle is a bit on the high side, about 1,200 RPM. There has been a bit more vibration at idle than there used to be. I attributed that to worn motor mounts. I've changed the rear/lower one a few times over the years, but not the other ones, which look pretty bad.

 

[Willie Williford]

Check the connection at the MAP sensor. The connection/line will get brittle at the end.

 

[*sean*]

The idle is a bit on the high side, about 1,200 RPM.

This can be caused by a small vacuum leak. It does not take much. Check the last work done (the EGR plate). Do you have any codes?

You should still check for exhaust backpressure with the vacuum gauge. With these cars there are often multiple issues.

If you do need to replace the cats because they melted, be sure you find and fix whatever problem led to that.

Good luck.

 

[jsloden]

Definitely sounds like a vacuum leak. You can usually take a can of brake clean or carb cleaner and spray around the intake and vacuum lines. If you find the leak with the spray the engine will rev up. This will help you find the leak.

 

[SlowSilver]

The car will be parked until I can figure out the problem. The volume of the hissing has increased, and the herky jerky issue is near constant. The exhaust has started smoking a bit as well. That has never happened before.

I'm planning on finding a new commute/delivery vehicle soon. Leaning towards a manual Honda Fit. The fuel economy will definitely not be as good, but being able to drive up hills without issues would be nice.

Hoping that I can get the issue fixed, but will probably still be listing the car for sale soon. It has a lot of good stuff on it, RE-92 tires with about half life left. Aftermarket cruise control that is currently not hooked up (was working until the transmission was dropped), something came disconnected somewhere. It has a grid charger as well. It also has new coil packs and spark plugs, as well as new front brake pads.

 

[Gasoline Fumes]

I'm planning on finding a new commute/delivery vehicle soon. Leaning towards a manual Honda Fit. The fuel economy will definitely not be as good, but being able to drive up hills without issues would be nice.

The Fit is a great car!

 

[SlowSilver]

I'm going to take a look at a third generation Honda Fit tomorrow, as well as a 2017 Mazda 3 hatchback with a 6-speed manual. The Mazda gets surprisingly similar fuel economy despite being a 1 liter bigger engine, much more power. My wife has a CX-5 and we love it. Those newer Mazdas are so nice inside.