I have only had my 89 auto for a couple months now and its been a bit of a headache. Ran ok when i bought it, not amazing. Now half of the time i drive it, it will hesitate, sputter, just run poor under acceleration. When i first got it, it would turn over a little longer than i thought it should when cold to start, i ran the first few tanks with seafoam and after the first or second tank it started up very fast. Now it still starts up fast cold but it will want to die after running a few seconds. It always runs after the first try. If i give it a little gas it will stay running then it idles fine. Warm it turns over a bit before firing up. My brake booster started hissing so i replaced it and i hoped in doing so it might run better after with a vacuum leak from the booster being the problem but it never changed the way it ran although it idles much better when the brake is pressed of course. After changing the booster it brakes way better but it shifts different, shifts at lower speeds now, too soon imo. So today i bought some carb cleaner to check for a vacuum leak hoping to find an answer to running poor. I sprayed it around all the lines i could find and never noticed the idle change at all. I also picked up a multimeter and check my injectors, 14.9-15.1 although i did notice that it looked that 2 of the injector connector plugs were crossed, so i swapped the connectors and fired it up. Seemed to run atleast as good, def not worse. Could this have been a problem? Im assuming that the order they are in matters but maybe not. I took it for a quick drive and ran ok, but its hard to tell yet bc the poor running problem is intermintent and sometimes runs good for a few days then will run poor all of a sudden. Anyways sorry for the long post but could this have caused it? I am planning on replacing the cap and rotor soon, wires and plugs also. Any input on my problems would be great, thanks

 

Does your SES light come on? Did you check for codes?

 

Injectors on an L98 are "bank-fire" so connection order doesn't matter functionally.

Before throwing parts at it you might try:
Clean the TB input & throttle blades.
Check the TPS setting at base idle (450RPM).
Check base timing.
Check fuel pressure and leak down.
Check manifold vac...with a gauge.
Verify warm idle is 600-700rpm.
For part throttle shift points, reset TV cable.
Change plugs & wires but I would leave cap & rotor unless a problem still exists and you have reason to suspect that area.

 

All 8 injectors are connected together and they all fire at the same time. It does not matter which connector goes on any one injector.

 

Ok thanks guys, i have no codes or lights what so ever. Starting to think something might be turned off or disconnected so i cant see them if thats possible?? There is a fuel pressure guage on the car and reads around 30 when running. Warms idle around 6-7 sounds right. It also has a bbk throttle body but i could try cleaning it. Previous owner said the fuel pump was changed not long ago and i also changed the fuel filter when i did an oil change....

 

Should be 40-47 psi when running. May have a leaking pulsator, it's between the pump and hard lines on sender/pump assembly.

 

Ok thanks, i just double checked the fuel pressure and its at 30. So i gather i need to pull the hole pump assy out to check it? (Im far from a mechanic). Thanks

 

You may want to check the fuel pressure with a hand held gauge just to make sure your getting a good reading,, I don't trust those small gauges......Like mentioned earlier, the fuel pressure should be at or above 40 lbs of pressure...Pull the small vacuum hose off the side of the fuel pressure regulator and see if you have fuel in that rubber hose, if you do then you have a bad diaphram...With pressure that low it's probably the diaphram ,fuel pump, or like "Agent86" says, it could be a leaking pulsator..If it's the pulsator you can just put a piece of fuel line in it's place, without causing any problems..As a matter of fact the replacement kits give you the rubber hose to replace the pulsator right in the kit. ..If it is the fuel pump that's bad, there's a company on this site called "Racetronics", you can buy a complete fuel pump kit for around $109.00, this gives you everything you need to install the pump, including new gaskets and hardware .It's a fairly easy job on a C4, took me less then 1 hour.....Good Luck....WW
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You can try some tests from the factory service manual, before tearing into anything.
Here is some info from my 86 manual

http://members.shaw.ca/corvette86/Fu...mDiagnosis.pdf

 

Thanks again! Wow i need to get an fsm, seems very good! Wheres the best place to get one? Cheaper the better!

 

Ebay has them for sale once in awhile, just do a search for Factory Service Manual for 89 Corvette....Guys also post them in this forums for sale section...WW