95 Chevy 5.7 with ignition problems??

I have a 95 truck with the 5.7 liter and sometimes when you first start it it sort of has a fit so to speak. It acts just like your turning the key off and on really quick. It is not missing. It is not the Distributer- just put a new one in.
I can't figure out what is wrong with it and my mechanic can't figure it out either. Also, when this happens, the truck will not shift correctly. It can do it at an idle...going down the hwy...or whenever. If it is doing it when you first start it...the truck seems to take off in 2nd gear or something and when on the hwy it will not shift into OD. The check engine light blinks on very, very fast when this is happening but leaves no codes stored.
NOW...if you start it and the truck is running fine...then it runs GREAT...and shifts perfectly. I'm stumped and so is my mechanic. The truck does have 238,000 miles on it.
Any help would be great...
Rob

I'd bet on the ignition switch or the wiring to it.

Thanks stickman. Is there anyway I can check the switch on the truck. I have not messed with it more yet. I live in the midwest and we just got hit really bad so I have to use it to get to work (4X4). If I start it and it freaks out...I just shut it off and restart it and then it seems to be fine. How weird is that?
Rob

Rob: Can't really see how you could check it since it's an intermintant thing. I know the switch on my '98 Sub has 5 different contacts internally that power different stuff. One of the reasons I suspect the switch is the tranny shifting problem as one of the 5 contacts powers the tranny electrical system. Been some folks on this forum who have cured similar problems by replacing the switch.

Some things I'd try when it's freek'n out is to try thumping on the column or a quick off-on while it's still rolling and running. I'm not saying a new switch will fix it but it would be the 1st thing I'd replace if I couldn't find anything else that was obvious like wiring problems (loose connectors or wires going into connectors).

Hope you get it figured out and let us know..........Steve

I put a new switch in it and it still has its fits like before. Does anyone have anyother ideas??

I'm wondering if you have a problem with your eprom/ecm. I'm having some intermitant starting problems which I was going to try do doggynose with my OTC scanner (see my thread http://www.automotiveforums.com/vbulletin/showthread.php?t=677074), but couldn't get a readout to the scanner. I didn't have a spare ecm or eprom for my truck, but one of the things I did was try an eprom from an 89 truck. My truck started and ran fine, mind you I didn't take it for a road test, but the SES light blinked like a strobe from back in the day. Actually I installed the ecm from the 89 also, and the truck started fine, but light blinked the same, and still no readout to the scanner.

I am now wandering if that is the problem too. I wish I knew someone that would have an ecm I could try out. I can't think of anyone that does. Can anyone check mine to see if it is good or not? or is it just a guessing kinda thing?
Rob

No help at all on ignition, but I love the 1992 lumina 5 Speed (1 of 200) It is a #3 Earnhardt car. It is only one of the show cars, not the track cars. I am having it repainted and need decals. I am in race city USA Mooresville, NC. Home of the Earnhardt's and I can't even find them. Thanx, Steve or stuff@MyWealthHealth.net.