brettmc

UPDATE IN POST 7

Background: Bought this car 12/2009 with fresh stock rebuild. Took the car to a local speed shop to install and tune an AI 200cc head/valvetrain pkg. I went with the 230/238 cam. Ignition components of unknown age, except the plugs are new.

Put about 100 miles on it after getting it back from the shop. No problems. Took the car out friday night for some cruising. It ran fine all night, probably put 150 miles on it. Topped off the tank with some Mobil premium and headed home. About 30 miles later, tooling along about 50 in 5th, the engine just cuts out. It's still running but no power and no response from the accelerator pedal and backfiring loudly out the exhaust. It does this for about 5-10 seconds while i'm downshifting to match speed & keep the engine from dying. Then it picks up and runs ok. About half a minute later, it does this again. It did this 5 or 6 times back-to-back like this. The last time it did it, there was a HUGE backfire, so big I could see the flash in my peripheral vision. After it recovered from that episode, it didn't do it any more all the way home. I took the long way and probably ran it 20 miles or so with no more problems.

Any ideas on wth is going on here? I know it didn't fix itself and it will happen again sooner or later.

Brett

garage_queen

iTrader: (3)

sounds like the rotor on the opti could be loose. Check all your grounds under the hood also.

AChotrod

iTrader: (17)

I agree with that.

jaycenk

iTrader: (1)

I would check the fuel pressure first. Not hard to do and will give you peice of mind. Then yea check the grounds, sometimes guys paint the block and load up the bolt hole that one of the main grounds goes to on the block and you need to run a tap through it and sand the surface a bit to get a good connection. It's located in the midle of the passenger engine mount. Also check the chassis grounds to make sure thier not rusted or painted. Then if that isn't it look at the opti like said above.

96ssindeed

I agree with the rotor theory. Had a car once that kept throwing the bolt on the rotor, when i was accelerating or cruising nothing would happen but when i let off the gas it would have a 2-step affect

brettmc

If the rotor were loose, wouldn't the stalling, backfiring be constant? Why would it straighten out and run fine like it did??

brettmc

I drove the formula to my new house and it sat for a week. I fired it up one day and it idled fine but died after a 5-10 minutes. It fired right back up and I let it run for another minute and shut it down. I was going to move it one day about a week later and it wouldn't fire. So, I pulled the opti over the course of a week (still getting settled in) and want to disassemble it. Then I noticed a date stamped on it...something like june 2007. It rotates ok but had some noticeable play in the shaft. I should probably core this one and get a new one. What do you guys say?

The weep hole was dry but I'm considering a new water pump too. Might as well replace it while it's apart, right? Any recommendations on the pump? What about a lifetime warranty o'reilly's unit?

brettmc

There's a fuel pressure gauge in the car and it read a constant 45 lbs when it was running...

brettmc

Grounds looked ok when I was under the car wrestling with the passenger fan...

z28camaro1996

iTrader: (1)

mine did that samething did the ses light come on?

brettmc

I don't remember seeing the ses light up.