hi, maybe someone could help me with this. 89 vette.
quick recent background of repairs/replacements: fuel pump, f press reg, 1 injector,all injector/fuel rail o-rings, plugs, cap, rotor, wires,k&n filter, tb bypass,fuel filter(twice),remove frisbee, lowered, vac lines, idle air control, maf, open air box, starter,Valv durablend, the latest being the injector and the press reg.
after dealing w/ numerous performance issues, the car is running great at this time. Strong out of the hole, pulls strong throught the rpm range.
after a few days, I was getting on my favorite freeway onramp, a line of cars behind as usual trying to keep up, now it's time to stand on it! much to my supprise, and the guy standing on it behind me, this thing practicaly throws me through the windshild. now the guy behind thinks i'm messing with him and issues me the bird. a quick shift to n (auto) it lights back off, shift to 2 stand on it again, same thing, feels like i'm towing a parachute underwater.
if i take off and drive like there's a cop behind me there's no noticeable problems. but try and stand on it the same bogging down. lift off the throttle it stumbles then returns to idle, stay in it and it dies. it will light back off. if i turn it off & go in a store, come back & try to start it, lites off for a second & dies. and that's all she wrote until it decides that it has finished it's nap. then it starts and runs as previously described. this behavior gets kind of embarrasing. makes me think about yanking this computer controled motor and dropping in an old rat motor (haha).
any ideas would be great. Thanks

 

Do you have stock injectors in the engine? In reading your words, it looks like you replaced one injector.....why did you replace this one injector?

 

Do you still have cats?

 

thanks for the reply. injector ohmed @ 3 ohms all others 13-18.
exhaust came w/ the car, but appears to have pre cats & cat (1) then 2 flowmasters.

 

rick, I'm not sure if i hit the right reply button last time, but it appears to have 2 pre cats-1 cat-2 flowmasters.

 

How much fuel is in the tank? The fuel guages on many of the older C4s are NOT accurate. You might have close to an empty tank even if the gauge reads closer to a half tank. If this is the case, upon acceleration, the fuel pump is sucking air and would cause the exact symptoms you are describing. It is a very common problem. Hopefully this is the case

 

just filled the tank. that's exactly what it feels like.

 

Check to see if you have any vacuum leaks. I had the same symptoms because the intake runner bolts loosened to the point I can turn them by hand. This was obviously after I took the whole plenum off and did away with the SuperRam. I'm not going through vacuum leak hell anymore. Also no more intake runner gaskets to worry about anymore.

 

thanks for the reply. I was going over all vac lines/connections, replacing suspected bad areas. every time i'd move one, one of those hard plastic ones would break. I finally replaced all w/ rubber vac hose. cleaned the maf, cleaned tb real good, cleaned all connections and now it's back running great.......F...ing Magic!

 

FF1wms: I hate to give you bad news when you say: "and now it's back running great.......F...ing Magic". You had one injector replaced because the resistance of the injector coil was only 3 ohms (this was a badly shorted coil). The other coils read between 13 and 18 ohms. You have some other coils starting to short out. The GM spec for Multec injector coil resistance is 17.0 +/-.5 ohm (if I recall correctly). The injectors in your car have a high failure rate due to shorting coils. Good luck dude and keep her 'tween the ditches.

 

I think clogged exhaust or poor/watered gas. Maybe fuel pump.

 

thanks for the info. i had a feeling about that since the only info i could find on them was their high failure rate and they should be r&r w/ something else. at the time i wasn't sure if the problem was any deeper (wiring, box etc.) so i took the least expensive route to have them work, $49. get this, i get the injector, install it and all o-rongs,fire it off and its smoking like crazy. after running it for a while i decided to pull it back out and check it again. i ohmed it before install. when i pulled it out i could blow straight through it. i should have taken that for a sign. have any recomendations on injectors reasonably priced? by the way this was only 2 weeks ago so all this is probably all the same problem.....maybe?

 

FF1wms: I will share with you what I did when I had your problem on my 89. I went to Mr. Goodwrench and priced replacement injectors....and they only asked $142......each for replacements. This was an easy decision for me. I asked Rich at Cruzin Performance for advice and he suggested I either purchase aftermarket injectors or get used Lucas style injectors from Corvette years 86 - 88 as these were very good and reliable injectors. I found a used set of injectors from a forum member from an 88 model (approx 30,000 miles) and I paid $80. Rich inspected the set for me and this cost another $30. He found they were a perfect matched set and did not need cleaning. I had heard negative feedback from aftermarked injectors and were afraid to try them. If you are pulling the runners to change out the injectors, this is not necessary. Send me an email to samlam@charter.net and I will send you info on how to do this....if you are interested. Running your car with shorted injectors can damage the ECM as the shorted injectors are drawing higher currents through the injector drivers. Owing a Corvette is a continual challenge.....but it is fun!!!

 

i just looked in the tank and there is a little water in it. how much would cause this problem?

 

thanks. I'll e-mail you.

 

Water in fuel looks like clear marbles of different size and shape, are you saying you can actually see this? If so you need to get an additive such as Heat..or some other treatment to remove it.

 

that's what it looks like. i'll put some heat through it. thanks.

 

You might be interested in this :
http://www.theinjectorperfector.net/

 

cool. thanks.

 

the stalling problem finally turned into a no-start situation. it turned out to be an ignition modual. at least during all this i found 1 bad injector and a couple on their way out. thanks to everybody for all the help.