94 formula backfiring/sputtering above 1800 rpm

[kansasvmax94]

my wife was driving the firebird today, (LT-1 Equiped) 100,000 miles on it, she said it was running fine, down the highway, and in a split second it started spitting and constantly backfiring. I drove it, it runs smooth idling, but if you take it on the road, once it hits around 1800 rpm, it starts sputtering and backfiring. any idea, would it possibly be the omni or whatever its called, if so, what kinda price am i looking at.

Thanks

[Craig 94 TA GT]

That would be my guess...the opti....especially if it's backfiring. However, if it's running poorly at that RPM, I would think you should see an SES light. Have you seen it?

[kansasvmax94]

im guessin SES stands for Service Engine Soon, and if thats true, no, no lights have lit. thats what threw me off.

[Joe 1320]

The factory plugs and wires are good to 100K miles, which is right at where you are at. Most likely time for plugs and wires, perhaps even an optispark distributor. Many times those problems won't set a SES light or a code.

For best discount pricing on GM parts:

Jason Cromer: 877-726-8295 or 850-243-8826 (direct parts dept ph #)
email: parts@samtaylor.com
Sam Taylor Buick/Cadillac Ft. Walton Beach, FL

or

Dal Slabaugh: 877-448-5451
email: lockitup@bright.net
VanDevere Buick/Pontiac/Olds Akron, OH

[Z Ya Later]

One more quick suggestion. Does the tach jump around when the car throws its little fit? Have you ever had any problem with the EGR valve at all? If so, try pushing on the diaphragm while the car is running to see what happens. I had a similar problem and it turned out to be my EGR valve sticking. Just another thing to check. Good luck man.

[94 formula]

I had almost the exact same experience as you with mine right at 98k. I changed plugs, wires, 02's, coil, and coil wire. Problem left then came back so I very stupidly bought a used opti and my problem got worse. Now my car is in storage till spring and I will be putting in a new opti and hopefully that will finally have my problem solved.

[kansasvmax94]

Thanks a lot guys, i guess i'll be looking into changing plugs/wires 1st. then if problem persists, opti unit. were is a good place to get opti unit, im a little ignorant to how it works. I really appreciate all your information everyone. Don't know what i'd do without the privilege of the F-Body Forum.

Thanks

P.S. - any helpful hints on plug changes, i've heard they're a bitch.

[94 formula]

Do a search on it to start with that should give you some good tips.

I dropped the starter and you have to take off the alternator to get at the #2 plug on the drivers side. A lot of people take off the y-pipe, but at 100k it may be risky that you may break off a stud on the manifold. Take your time have a case of beer and some band-aids lol. Also some plug wires aren't fun to run, but be careful with them take your time and you'll get it all done. The drivers side isn't that bad but its the passenger side you need take your time with. Also www.gmpartsdirect.com and www.samtaylor.com are great places to get parts for a low cost.