'95 LT1 Auto KN/openlid TB bypass I'm not really sure how this car should sound at idle or should I say 'feel' at idle. Sitting in gear after driving for awhile, all acc off, there is a little intermitent stutter(?) that can be felt thru the steering wheel. I thought I could see the tach needle move, but if it did it wasn't very much. I cleaned the TB a month ago and don't remember feeling it then. Noticed it yesterday. It doesn't hesitate when you give it the gas, and it doesn't appear to be a miss. I haven't been in another vett to know if this is normal or not, and not knowing bugs the hell out of me. I'm a little **** when it comes to this car so if you've got any comments/suggestions I'd sure like to hear them.

 

It may be dirty fuel injectors...

I'm not a mechanic (and don't play one on TV either ;) ) but here's what I did when I had the same problem on my 85 and also on my girl's 89.

Go buy a can of fuel injector cleaner and dump it in the gas tank with about a 1/4 tank of gas. Then go find a desetred road where you can run it hard. Opens the injectors 100% and cleans them right out.

This may not be the "correct" way to clean the injectors, but it sure worked for me

:D

 

What brand cleaner did you use? If it's tried and true I'd like to stick with a known. Apreciate the response, thanx

 

I don't remember the specific brand, but it wasn't from K-Mart. I suspect any good name brand would do. The trick is to have only a small amount of fuel in the tank so the cleaner is more concentrated.

Then WOT for as far as you can, the idea is to flush the varnish off of the injectors.

Good luck and let me know how it turns out...

 

Hmmm, I believe your 95 has self-cleaning injectors. Using a cleaner can damage the injector.

Let me see if I can find the info on this and post a follow-up.

:seeya

 

Thanks

 

Source: Corvette Service Manual.

The SFI injectors (primary and secondar) are solenoid-operated metering valves, controlled by the ECM. The ECM energizes the injector solenoid, which opens a ball valve, allowing fluel to flow past the ball valve and through a recessed flow director plate. The director plate has six machined holes that control the fuel flow, generating a conical spray pattern of finely atomized fuel at the injector tip.

The primary's are in operation during engine crank and during engine operating range. The secondary's are enabled by the ECM only during periods of high engine speed and load.

NOTICE: Use care in removing injectors to prevent damage to the electrical connector pins on the injector and the nozzle. The fuel injector is serviced as a complete assembly only. Since it is an electrical component, do not immerse it in any type of cleaner.


I believe that these models are Rochester brand instead of the Bosch. Because they are an electrical component, with a ball valve they don't require cleaning and continued use of cleaners will damage the coils.

Here's a link to a lot of info on cleaning the injectors. Note that they use ultra-sonic cleaning. I would refer to the details of the service manual to remove and install the injectors.

I think if you review the data on the link below, you can see that there's a little more to it that one would think.

http://www.cruzinperformance.com/fuelinj.html

Hope this helps. :seeya


[Modified by 93JetJocky, 7:25 PM 11/10/2003]

 

For some reason a lot of '95's seem to have a slight roving skip, not a true miss, in the idle and/or idle exhaust note. Mine does. Out of gear in neutral or park (automatic trans) it cna be heard a faint chuggle every now and then from either muffler tip, but you have to listen for it. Put her in gear with the e-brake set and it goes away or at least diminishes to the point of inaudibility. Last visit to the dealer service shop when i was having some transmission work done under GMPP ext warranty (only reason it was a dealer shop-- 'cause of the GM ext warranty), I had their top LT1 guy (he owns, races, mods, and wrenches a '95 Z28) take a look. He listened intently putting it in and out of gear, etc., paused, and proclaimed it to be a "normal condition." Said his Camaro used to do it too back when it was stock, and he could never find a source. My mpg is within spec, it pulls well, so I've learned to accept it, if not embrace it. My car has a new opti, plug wires (stock Delco), coil, new plugs (AC Rapidfires)... basically new ignition system except for the ICM, and it still does it. Prior to the professional opinion I traced vacuum lines till blue in the face, tested w/ EGR valve removed and the EGR port blocked at idle (incase EGR leaking @ idle), replaced PCV valve, replaced TPS, checked MAF sensor, cleaned throttle body and IAC, including IAC port in the throttle body. Only thing left is the oxygen sensors and since my mpg is okay (avg 18 - 19 in town) I can't see it being them.

Not hijacking your thread, just using my experience with the issue as an example. :cheers:

 

I asked this question a while back too. My 96 does not have a completely smooth idle. Lone Ranger described it very well. My car runs fine, so for now I'm leaving well enough alone. It has been this way since I bought it in April, I've put on approx. 7,000 miles since then, and the slight skip every now and then remains the same.

 

Opps I too forgot to comment on the original issue... I'm with LR, I get the same thing, sometimes there seems to be this minor miss, can't see it on the tach but you can feel and hear it, then sometimes you never hear/feel it. Some days she just purr's perfectly, some days I notice it. I have done a lot of the same new NGK plugs, Taylor wires, cleaned TB and IAC, new opti. I've just learned to accept that its a characteristic of the engine.

Got side tracked on that injector stuff. :seeya

 

Thanks to all who responded. I feel better that I'm not alone(or crazy). If it ain't broke, don't fix it. Whatever it is doesn't effect the performance and gas milage is 25mpg hiway @ 75mph. I'll live with it. Cars seem to be a lot like people, they perform better on certain days than on others. Once again the forum comes thru.