LT4 LT4 hesitation

[Vettelt193]

I am getting a bit of a hesitation at low RPM's. It is especially noticable when the car is cold (less than 160). It seems to be missing that low end grunt that it used to have. Is there something that stands out with this problem?

I have 46k miles, K&N w/open box, performance MAF, muffler eliminators.
My check engine soon light is on, but it has been since I have had the car (as a matter of fact, every C4 I have owned has had that stinkin light on!). I think the check engine light is A/C related, because if I don't run the A/C for a few days, it goes off... as soon as I turn the A/C back on, it throws the check engine light again.

 

[BaddogLT4]

I hate check engine lights, but the good news is that it should be easy to find out what that problem is. Find somebody with a scanner or buy one and it should tell you what is wrong. If it doesn't happen all the time, you can buy these modules that plug into the car and when you do throw the check engine light then you can download all the information to your computer and see what's happening.

As far as the hesitation, that's more difficult. I would look at the following, possible bad spark plug, wires, or it could be a problem with an injector. I'm not a mechanic, but these are the things I would look at. "Good Luck".

 

[jplay]

i had the same problems when my egr valve was bad, and similar things happened when my opti was going.

 

[Vettelt193]

I hope it isn't the opti... i will check the EGR valve... I didn't think of that

 

[jplay]

im not sure but i think there are 2 of them

 

[FX GS]

... i will check the EGR valve... I didn't think of that

That might be tough to do..........LT4's do not have an EGR

 

[Vettelt193]

That might be tough to do..........LT4's do not have an EGR

I remember that now. Don't know what jplay did to his car though:confused

I got on it last night on my way home from work... It has been quite some time that I have run my 'Vette hard and up to high RPM's. It seems to be running a bit better today. I need to get this thing out to the track (I wish there was one close by me). I think it needs to be run more than anything else

 

[Tuna]

When was the throttle body last cleaned?
How about an new fuel filter and fuel system cleaner?
What codes are set?

 

[Vettelt193]

When was the throttle body last cleaned?
How about an new fuel filter and fuel system cleaner?
What codes are set?

Let me just say that I have been a lazy SOB lately.

fuel filter = original I gotta get that changed this weekend!
I haven't cleaned the TB in a while. I will add that to my list too.
I will throw some Techron in the gas, that is my preferred fuel system cleaner (as far as the in-tank stuff goes)

I also need to get the tranny fluid changed, but still have not been able to get the dang fill and drain plugs loose... any ideas? I put all my weight into them, and they just won't budge

 

[jplay]

whats the name of the piece by the back of the motor that black metal and looks like a small candle holder

 

[Vettelt193]

whats the name of the piece by the back of the motor that black metal and looks like a small candle holder

no idea... sorry :confused

 

[jplay]

ill take a picture when i get home tonight and post it

 

[Vettelt193]

I know what you are talking about, just don't know what the heck it is

 

[CKA_Racing]

Check your spark plugs. The little puck on the electrode may have fallen off. Had them happen twice in 40,000 miles. Assuming you have OEM plugs.

 

[Vettelt193]

Check your spark plugs. The little puck on the electrode may have fallen off. Had them happen twice in 40,000 miles. Assuming you have OEM plugs.

yes, they are stock... that is the last place I am going to go though... I hate changing plugs on LT1/4 corvettes. It is the one regular maintenance item that I gladly fork over $$$ to have someone else do

 

[froggy47]

I would add some Redline (is it total engine cleaner - or something like that) to the Techron & run the sob hard. I've got 55k on mine & autox once a month. Hesitate - don't know the word.


You may need a serious injector service but the techron & redline might do it too.

Let us know when she's right again & how you did it.

Did someone say - air cleaner?