The car runs fine for several miles/minutes, suddenly the tach starts to climb, up a jump, then up again. This is when the engine starts to run really rough and I pull off the road, let the car cool down and make it the rest of the way to work (about 15 miles).
Here is what I have done: Radiator flush and fill; Oil and filter change; Cleaned EGR and replaced gasket; put in new spark plugs; changed the transmission filter and oil; replaced the O2 upstream and downstream sensors; replaced the thermostat 195 to 180; replace the coolant temp sensor.
The check engine light does not come on (except on start-up check sequence), so it is working. Their are no trouble codes (other than when I removed the downstream O2 sensor to check if I would get errors). The cat converter doesn’t glow at night, and doesn’t rattle when tapped. The resonator in the exhaust does make a rattling sound, but I don’t see why that would be the problem.
I am at my wits end. Does anybody have any clue what I should try next? The water pump isn’t leaking. HELP, HELP – please!