It's a '96 LT4 here's the background and the symptoms:

approximately one-two months ago the car started having a very rare and very slight stumble at light throttle loads. I believe this was cause by my then locked up AC clutch dragging on the belt. It appeared to go away after I fixed that.

Approximately 3 weeks ago I rolled through a moderate puddle and the car died. The car wouldn't start for approx. 45 minutes. I assume I got the opti wet here. However, once dry the car only ran rough for a few seconds and was fine after that.

Skip about a week, the car is often a little hard to start. I attributed this to the ECT sensor I broke off the water pump. However, this went away when I rigged it back up.

Skip about two week to present, it's raining lightly, the car is hard to start when I leave school but starts fine a few minutes later. I go race karts at Davy Jones (you should definitely go there if you are in the houston area) and the car is very hard to start when I try to leave, won't hold idle and dies twice with me trying to keep it running. After a few minutes it evens out. On the way home it stumbles some on the highway but feels like it will be OK. Then as I exit the highway turning like 2500 in 5th it just dies. Hard to restart and dies like 4 more times in the 10-15 blocks to my house. Vary bad barely made it.

Three of my next four trips were the same. Then the next two times it starts and runs fine like nothing's ever been wrong. When running crappy the voltage fluctuates and often the AC starts blowing hot. Also I have a horrible power steering leak that is soaking everything that I am fixing this weekend.

My ideas are:

opti, I hope not but maybe ruined from getting wet with water or oil

Alternator: maybe from oil getting inside

plug wires, I have one with a burned spot but it's been fine for years, also I am replacing these this weekend

ECT sensor, Planning on replacing this weekend as it is cheap.

A bad vacuum leak I have in a rubber elbow that comes out of the middle of the driver's side of the intake manifold, planning of fixing this weekend.

Bad gas, maybe?


Anyway, If anyone has any other ideas or can narrow it down please let me know. Thanks a ton for reading this long winded message.

Jason Saunders

 

Since your Opti is new & improved I suspect those wires.

 

Sounds like an opti going out to me. :rolleyes:

 

Pull the codes and see if you are getting any low or high resolution faults. This will send us to the opti. Moisture and problems can mean a secondary spark issue, even bad plug wires. Pull the car into a darkened garage, idle, and look around the wires. I've seen sparks jumping around bad wires. With the stall at 2500RPM though, suspect something else is going on. Still, good idea to change the wires if they have been around over 60k. At some point, your fuel pressure readings would be nice to know. Darn cars.

dlmeyers 90 coupe zf6 3 speed shocks

 

I would love to pull the codes but I haven't sprung for the 250 in software yet.

Also, the last five times I have driven it it's run without a hiccup.

Thanks for the help, although I'm gonna be pissed if it's the opti. After reading some old threads I was thinking maybe MAF. people seemed to be reporting similar symptoms caused by bad MAFs.

Jason

 

How many miles?

Opti troubles seem to be indicated when seemingly random problems are occuring. This also can indicate a PCM problem as well.

I don't know how heat resistant the seals on the later optis are, but the early ones get cooked, hard, brittle. Then all sorts of stuff can get into it. The later seals look to be a better design, maybe they are better material.

After 4 months of running on 6 or 7 cylinders sometimes, rough idling, occasional stalls, occasional rough or not starts, I diagnosed my opti by pulling the air supply line from the air intake while it was running rough and giving it a blast of air from a can of compressed air that I use to clean my keyboards. Before the air, rough idle, after air smooth as silk (for a couple of minutes), more air more smooth idle. Replaced opti, smooth ever since.

 

The ignition coil is a common problem also. Perform visual inspection and look for white deposits between the outer metal ring and the plastic inner coil itself.

 

A little update. I think my problem may be a bad fuel pressure regulator. After I finished working on it this weekend it was dripping a substantial amount of fuel. My other guess is that my vacuum leak was preventing my opti from being properly vented. ANyway, this week I will fix all the little crap and see if it acts up again.

Thanks for everyone's help.

Jason