Ok this started happening a few days ago. I'm a beginner at car repair so bear with me. Well when I let off my gas my car kind of sputters down and sounds like you know a lopy car with a carb. This has gotton progressively worse. The car seems to skip when cruising at a constant speed and sputters and almost dies somtimes when the gas is released. I have noticed decreased acceleration. The car sounds like it's running rich to me. The exhaust makes a more gurgled noise. I just replaced my wires, plugs, fuel filter, oil, and oil filter thinking that might help it but did nothing. The car has a slight miss at idle as well. Could this be a bad distributor? I am stumped here and need help. This car is daily driver and I need it. Any ideas on what might be the problem?

 

I had similar symptoms when vacuum line under the plenum came apart. I would also check fuel pressure.

 

How would I go about checking the fuel pressure? Which line under the plenum should I check?

 

There is a small diameter black plastic tube that runs under the plenum from back by the distributor, to the EGR (under the plenum) and then to the throttle body. There are several push in connectors along the route. Mine came unplugged near the throttle body. As far as fuel pressure, a gauge that permanently connects to the fuel rail is the best to have, and a must with an adjustable fuel pressure regulator. My car used to stall often at idle. I put the gauge and adjustable regulator on at the same time, so I don't know what it actually was before, but with the higher pressure the stalling has ceased. I once read that fuel pressure is the first thing that should be checked because everything else runs on the assumtion that the pressure is within the range it should be.

 

What else do you think it might be if it is not that line? Would a bad distributor be the cause? What about timing chain? I don't have much cash right now and I really need this car running right. Thanks for the help so far. I will check the line tom to see how it is.

 

I'm not really that a good a troubleshooter, so I'm only commenting on things I've experienced. Hopefully some other guys will jump in here and help out. Let us know how you make out.

 

Thanks KNTA4DNU for your advice. If anyone has any ideas please post them. I need to try to fix this as soon as possible. Thanks.

 

Is it HO, or is it TPI? The HO motor is carbed, and if you have a 305 TPI auto, then it's the lowest output version of TPI. You should fix your sig to be accurate. Leave the HO off if your motor is not a L69.

I'm going to assume for the moment that it's the usual TPI auto with the peanut cam.

First: a vacuum leak will not affect WOT performance. If WOT isn't right, then there is something else wrong besides (or in addition to) a bad vacuum line. If WOT was fine but idle and cruise were affected, then a vacuum leak would be a definite possibility.

Try unplugging the injectors one at a time with the engine idling. Each one should have the same (bad) effect on idle quality. If any of them seems to affect the idle less than the others, then it's bad. Send them to Rich at www.cruzinperformance.com or better yet, find yourself a set of stock Mustang 302 ones and send him those, and tell him you're putting them in a GM car so he will supply the right O-rings. They work about 100 times better than the crappy Multec ones that GM uses.

If all 8 injectors seem to be working about the same, do a compression test next.

 

If it is for sure a TPI fuel pressure is pretty important and easy to check. I was having very similiar symptoms and it was my fuel pump going out. I think the pressure should be about 40 psi. Check a manual to make sure. If I remember right mine had fallen to below 30. I would check that before racking my brain on ignition issues. Good luck.

 

Well I checked the vacuum lines and all of them seem to be connected and in good shape. This happens at cruising and when I let off the gas. It doesn't really miss when the car is gaining RPMs but the car isn't pulling as hard either. So I guess I'm going to have to go get a fuel pressure gauge and see what I am running at. I attach it to the nipple on the fuel rail right?

 

ye, if I remember right it is on the passenger side.