bad map sensor 91accord?
 

Hello I'm new here so hello. I have a 91accord EX been having some trouble with it was hoping mayb I could get some help here. Car has been running bad usually after it has warmed up. When cold it runs just fine sometimes but sometimes not so good. After warming up is when the trouble starts. It will accelerate poorly and often I can't get the rpms up to 3500 sometimes it won't get up past 2500rpms. It don't stall or anything but looses almost all power. When it starts doing this it makes a sound like its sucking or blowing air best way for me to describe the sound is it sounds kinda like a leaky air hose not a big leak just kinda a small hissing or maybe sounds like the turbos on a deisl engine. The sound is most noticeable when the rpms start getting around 2500-3000 and the enginge starts loosing power. Its got 5speed manual tranny if I put in neutral it will wind up and rpms go up like they should and sounds normal and seems to run fine till put back in gear. The check engine light and charge light have blinked randomly since I bought the car little over year ago. I was gonna try and figure out the codes when I started having the problem.was told to unplug battery to clear them then check codes when they start flashing agin its been 2 weeks and engine lights havnt blinked since. Its been suggested maybe the map sensor but the mechanic who took it for a ride wasn't sure and had him baffled. Any help or advice would be greatly appreciated.

I replaced the fuel filter and pcv valve as well as checked my vacume lines and air intake thinking that maybe where the hissing noise was coming from and they all seemed to be in good shape with no signs of leaks or blockages in air intake

Just me but the MAP sensors on these do not got bad very often.....

Before clearing codes....you should at least note the ones that are stored.....then clear and see if the same or different codes come back.

Anyway, a stab in the dark here......unplug the O2 sensor and drive the car. Does it act up or drive ok? Yes this should set a code in the ECU. Once done with the drive, check to codes and then clear.....let us know what you find out.

Thanks poorman I'll try that and report back. And if that's you in your avatar pic thank you for your service.

That is a pic of my oldest son after graduation from OCS USMC.

So I unhooked o2 sensor took for drive right away it started running bad didn't go but 2 miles and it got real bad turned around barely made it home. Checked the code got 4 longs and a short so that would be a 41 right? Hooked sensor back up cleared the codes went for a drive, ran great for 20 minutes then last 5 minutes back to home started running bad agin. But no check engine lights came and no codes.

Could it be o2 sensor?

You got a code 41 when unplugging the O2 sensor.

If you have no codes, then the sensor is not likely the culprit in my opinion.

Does the D4 or S light start flashing while driving? Do you ever get codes from those lights when you check for the engine codes?

I'm not sure what d4 or s light are but when I checked codes just the check engine light blinked

If your car is a manual transmission, then you won't have those lights.

If the car is an automatic, then the D4 light is the light in the cluster when you put the car into drive. The S light is the light that turns on when you press the sport shift button on the gear selector.