1987 chev celebrity. 150,000 miles. V-6. Auto trans. Car starts right up and idles smoothly. No hesitation, surge, backfire or dying. Severe lack of power under acceleration. Plugs recently replaced. Plug wires as well. Air cleaner too. Also recent fuel pump. Whirring sound from engine as if it is working too hard. When revved high in neutral, sounds like it is sucking air. Revs high then shifts late, when driving. Oil and transmisision fluids look to be normal. No engine smoke. No detected fluid or exhaust leaks found. Car drives just fine except when you try to accelerate, then it bogs down and very slowly reaches speed. Struggles to reach freeway speed, but after doing so, runs wiith no problem. No other unusual noise from under the hood.
Could be excessive backpressure due to a partially plugged catyletic converter. Could also be a fuel pressure problem. Loosen the bolts before the cat in the exhaust and drive it (itll be a little loud). Other than that it will need a manual fuel pressure gauge to verify correct press.
January, 10, 2007 AT 10:07 AM
This may be poor engine performance.
Low engine vacuum will cause a vacuum modulator to sense a load condition when it is actually not present. This will cause delayed and harsh shift. Delayed shifts can also result from action of the throttle valve assembly, if the engine runs so badly that the trottle pedal must be frequently pushed to the floor to keep it runing or to get it going.
Check your the fuel pressure first, and also check if the catalytic converter is plugged, because that could cause the same problems.