When driving my '91 Prelude, the engine bogs down when I hit 3500 rps, every time. At first, it only happened sporadically. Now it always does it.

When I say bogs down, I mean it! Almost got into a bad accident with my teenage daughter and 3 of her friends trying to pull out and cross a street!

I've changed the fuel filter, spark plugs, distributor and rotor, and maybe something else?? The only noticeable difference was not a god one! I basically wasted almost $300 for nothing! I can't afford to do that EVER!

My mechanic of over 15 years thinks it MAY be the engine computer, or ECU, from what I've seen so far. However he isn't sure. He also tells me theres no guarantee if I get a used one that it will: 1) solve the problem; 2) be an operable ECU! So how does that work? If it's defective (the new one), am I simply screwed???

Is there any way to test the computer to see if that's the problem? The Check Engine light doesn't come on, so I guess there's no code to read, right??

I'm very concerned, since my mechanic is so unsure about where to go from here. I know he's just trying to save me money, but I need his guidance about what to do. If he doesn't know, I sure don't! This man only works on imports in his garage and I've never, in over 15 years, seen him stumped on my Prelude!

All advice is welcome and will be discussed ad nauseum with my guy friends. Thanks!

 

Things I would check would be the ignition coil (and all wires related to it), the ignitor/ICM inside the distributor, and maybe the ignition switch. Those might help if it's an electrical issue.

You might also check your timing as bogging is a good symptom of bad timing. Your timing belt could also just be old and stretchig a bit causing the bogging, how long's it been since it was changed?

Those are just some ideas, hope it helps.