GAWD this is REALLY gettin on my nerves! Ok, here's the situation. First my car was running like complete crap so we thought it was the opti. Well, we replaced the opti only to have the same problem right away. We then found the actual problem..a broken valve spring. So, we replace the valve spring and all seems fine. Drive it around for awhile (about 45 min) and it just dies for no reason. Running great then dead. Well, we check all the connections but can't find anything....get back in the car 15 min later and it fires right up and runs fine Ok, so the next day I drive it again....after 45 min it dies...I wait awhile and it starts back up however this time its running like it has a clogged cat (but I don't have a cat ) so I hobble home and the next morning I start it up to put it on the ramps...well, it starts right up and I go to put it on the ramps but one of the ramps move a little so I have to back off. I shut off the car to reposition the ramps and try to restart it but it won't start (and its cold...only ran for maybe a minute ) So since I just replaced the opti, I replaced the coil and module. Drive it 45 min and it dies. We decide to swap out the opti (maybe the opti was DOA) Now when I drive it, once it gets warm, it acts like the cat is clogged but of course, it can't be. I can push in on the clutch and hit the gas and it goes up in the RPM's fine..no miss...but just cruising in gear it runs like its got a miss or bad cat. I checked the plug wires and also looked for arching (but its only stumbling when its held at speed...no other time) Anybody have any suggestions???

Thanks in advance!

'95 T/A M6, LT4 Hotcam kit, Ported/Polished heads, LT4 valves, TPIS headers, 52mmtb, !CAT, LT4 km, Flowmaster, custom tune

 

This sounds like a fuel delivery issue and not a clogged cat. Have the fuel pressure checked and also look at the vacuum line from the intake manifold to the fuel pressure regulator. Make sure the fuel tank filler neck cap is good. I wouldn't think it's the opti since your car runs fine for a while. Make sure those plug wires are not burned. You can get a good look from all sides with an inspection mirror.

 

Thanks for the reply Yea, it couldn't be a clogged cat because I removed it and have a straight pipe there I was thinking about a fuel problem (and I'll check the pressure) but if it was a fuel problem wouldn't it do it all the time not just when it gets warm? BTW, does anyone have the specs on what the fuel pressure should be at?

Thanks again!