My 99 LE has a perplexing engine issue and was hoping somebody may have insight on it. The engine won't rev more than 4500 RPM. The redline is about 6000 RPM. The car was overhauled due to oil starvation by the previous owner. The overhauled engine starts fine and runs completely normal until it gets above 4500RPM when it sputters and misses. There are no engine codes and no check engine light. I don't usually drive the car at that RPM but it is needed when gearing down to pass or climb a canyon. I've double checked timing, replaced plugs and wires, MAP sensor, and can find no vacuum leaks. The catalytic converter is not restricted. Compression is in spec on all cylinders. Ideas! Anyone!!
Thanks

 

I am curious, how do you know the converter is not clogged? I was driving my Mom's Cadillac back from the airport one day back in the 1980's and I was doing about 70 mph on the highway. After about 20 minutes, the car was sputtering and slowing down. After a few minutes, It got so I had to keep pressing the pedal down further and further just to maintain 60 mph. Soon, the pedal was to the floor and were were only going 45 mph. (about 1,500 rpm) That's all it would do. I pulled over and shut it off and restarted it and it started up fine. It ran just fine until about 1,500 rpm and I drove the rest of the way home at about 40 mph. Replaced the converter and it would do over 100 mph again easily. I am not saying it is your converter, I am just wondering how you know it isn't. You might want to check on the crankshaft position sensor to make sure they put it back in the correct position and the wires are not broken.

Bill

 

Did this engine ever run right since you had the car?

 

Thanks for your input Bill. I took the car to the Toyota dealer. For their initial check they confirmed no blockage in the CAT, and did a vacuum leak test. Both tests passed. No obvious broken wires on the crank sensor but if the crank sensor is bad I think it would not run at all or maybe run terrible at all speeds. Next obvious step would be to change the fuel filter and check fuel pressure.

 

The engine was seized when I bought the car. The original engine had connecting rod bearing damage (spun bearing) on the #3 cylinder. The crankshaft was damaged so I salvaged a used engine at the salvage yard and rebuilt that engine and installed it. The car started and ran smoothly until it hit 4500RPM during the test drive. I was thinking that it might be fuel related. Maybe the fuel pressure is low. I've changed the fuel pressure regulator but need to change the fuel filter and check fuel pressure.

 

Ok, so not the cat. (Probably good news) I had a doge van once that would not go over 3,00 rpm in any gear, it was fine for 30 miles when I got it but suddenly happened one day. I had to take that to the doge dealer to get diagnosed and, it was the crankshaft position sensor. It did not throw a code either but, that was back in the OBD1 days so things may be different now. Probably not in your case but I was just tossing it out there as it had me totally stumped at the time. Took the dealer a while to figure it out also. Sorry, I am out of ideas. Good luck.

Bill

 

Thanks! Not too hard to change the crank sensor. Worth a try!