Guys, I've got an 88 Formula 350(L98). First of this car for me. It won't idle for a long time till its warm. It often sputters below 2K rpm. I don't know why??? It has new plug wires/cap/distributor/ignition coil. (I'm working on the plugs now, they're hard! lol) It also appears the MAF has been replaced, it looks newer and is a bosch. I tapped on it when the engine is running and it makes no difference at all. The car is basically all factory except a borla cat back. The old owner treated the car like crap. One cylinder was unplugged!!! One of the plugs I pulled was slightly white... Does this mean its running lean? Is this a result of the exhaust? Is the sputtering and jerking a result of fuel delivery failure? The problem only seems to exist below 2K-2200rpm's. Once it clears that mark, it runs like a champ! Also if it begins to sputter while driving, the problem can be temporarily cured by pulling over and shutting the car off (normally for 10sec). It usually starts back up and will run fine at least for a few minutes. CEL will flicker on and off but is never consistent. Could it be the MAF wiring? I don't know this engine well and your guys opinion and help will be really appreciated. Last random question, its an Auto Tranny, so what is the code? L460/700R/700R4???

I'm really sorry for the long first post, but every time I search for info this forum comes up and you guys seem to really know the deal. Thanks in advance.

-J

 

my car is doing the same exact thing, mine is a 88 GTA tho but exactly the same setup i replaced everything you replaced and still have the problem. my buddy has a 87 GTA that did the same thing, he fixed his wit replacing the vaccum hoses going to and from the intake manifold i havent tried that yet, dont have time. try looking for holes that could be as small as a pin head small idk. thats jus a suggestion to check. if it works for you let me kno.

 

Yeah, I've heard of this being caused by vacuum issues. I've not replaced all the lines yet but plan too. Mine seems to be happening less and less frequently though lately and I'm on my third or fourth tank of 93 octane fuel (I've only had the car for about 10days).

Is 10mpg usual for our engine?

 

Mine seems to happen mainly when there is fresh cool air outside. but on a normal cloud free day wit the sun shining it will run like a champ lol.. this problem has had me stumped for a while too its been doing it since december.

i think u should be getting more mpg than that though. im not sure wat i get but it does good highway and decent in town if i dont hot rod it. but when it acts up it goes through gas like crazy.

 

Well the funny thing my Formula has been running better and better lately. I'm on my 4th tank of premium and I think I'm cleaning the moisture and junk out of the tank. Do you keep the car full? I use mine as a DD (crazy I know). And so I'm ripping through gas pretty well. Next step is replacing the fuel filter. Then Vortec heads!!! lol

TKR88, it might be moisture in the tank

 

did you scan the car.. you said you have a CEL.. advance or autozone will scan your car
if you do not have one... that would be a lean indication check you fuel pressure!!!!
have you changed the F.F. lately

 

Thanks gta88, the CEL is oly on at idle, otherwise I don't have one. And the engine has been running significantly better. Next step is FF! Its sitting in the back seat. Any idea where on the car it is?

 

the autozone here cant scan my car its to old they say.. dumb i kno.. i use mine as a daily driver too so ya i go through a good amount of gas as well. the last time i changed my fuel filter was back in august i think..

n its funny i still smoked a civic down here wit it acting up n surging like crazy with out my top end power i laughed lol...

New style, how did u find out it could be moisture in the gas tank??

 

TKR 88, when I got the car, I drove it to a gas station filled it with premium and proceeded to drive 160mi home (borrow plate lol) About 2mi from home, the car started to sputter and it was right at the end of the tank. It continued to do this for the next couple of tanks of gas. I'm an import guy (first muscle car) but my Dad is old school. He said run a ton of dry gas and gas through the car. I did and WHAHOO!!! So now I always run a full tank and immediately fill back up. That doesn't allow much moisture to gather in the tank (Central NY is bad...) Problem could also be:
Dirty/junk injectors
MAF/MAP
Fuel pump
Clogged FF
Vacuum Leak

 

Glad you smoked that guy. I don't car what kind of car I/my friends are driving I always gotta win! I've been having a blast with all the TQ though. She slides a ton!!!!

 

im gonna try and check the vaccum leak this weekend. so your running a full take all the time and thats been working for u? i run like half alot sometimes a 1/4. n i run 87 octane and sometimes 91... idk if thats messing things up too. i tried injector cleaner and that cleared it up for a while and it came bak the next day.

 

I know running a full tank can be hard on the wallet, but it keeps the tank clear of moisture, sounds like thats what your running into. You don't need to keep the tank full all the time, just run full tanks. When you go, fill it up all the way. It'll begin to clear things out. Check your FF too. And maybe the next two tanks, run a can of dry gas/heat for each one. I bet you find it'll helps. Though it may be something else, it sounds like with the injector cleaner experience thats likely your problem.

 

well a couple weeks ago i drove my car on a trip for 5 hours up n 5 hours bak n i kept the tank full i didnt let it go down past half n it ran good didnt act up. it was good weather tho n even wit an elevation change of about 1500 ft still ran good. but idk i got bak to town it acted up once but thats it. so idk its bee pretty sunny days too. so im not sure y exactly my car does it yet...

sorry for the long wait for the update i barely got to a computer but has urs acted up since then?