I know we've had many posts bout opti problems so I'll try one more. I'm suffering from high rpm hesitation/sumbling at the top of every gear and at wot sometimes and the dealer told me that I have random misfires occuring but couldn't figure out why. They occur in mainly #3, and somtimes in other cylinders. I've changed plugs already two different times, wires twice, installed an MSD coil, cap & rotor, and fuel inj. service. Problem didn't occur till after the dealer installed a new opti but they tell me it's fine. Could this at all be a fuel related problem? Maybe bad or worn out injectors could cause this. My car has had the motor replaced due to a timing chain failure and now has about 60k miles on it. But the injectors have about 147k miles. I would appreciate any help as I'm trying to have the car in tip top shape for SLP day in April.

96 SS #667 A4
Mods: crane 1.6rr's, 2800 vigilante, 52mm tb, slp cai, aluminum ds, lakewood ph & lca's, bbk 1 5/8 headers, msd coil, taylor 8m wires, hypertech pp, 160 stat, slp 2otl exhaust, 3:42 gearing

Best run: 13.51 @102 60ft: 1.8 (st tires)

 

What caused them to replace the opti in the first place? I would be highly suspect of the item they replaced and then the problem showed up.

By the way, if you want them to replace the opti (if it has some sort of warranty) but they insist it's ok you could always rig it.

Let me ask what other sensors have or have not been replaced? TPS, MAP, O2's?

The injectors are easy to clean from the fuel rail. If you don't have the kit, seek out a shop that has one. It only takes 20 minutes to do. The cleaner costs 16 bucks and 20 minutes mechanic time.

 

Not trying to be a smart a$$.Did you try a search?I have seen this problem a lot on here.

 

I've replaced all the O2's and check valves, and replaced both cats.

 

Any codes?Does your SES light flash?TTT 4 you.