Car bogging while driving, Help!!

[V8 Killer]

Car bogging while driving, Help!!
Car is a '91 V6 Firebird. As im driving sometimes (just started recently) once I get past about 3K RPM, the car may start to bog and almost seems like its dying. Usally happens at about 50 mph, it drops to 30 mph when it bogs, then go back up to 50, then bogs down again. and starts to drive normally again.. I had a SES light a few days ago, it went away after an hour of driving. I unlocked it by using that key thingy and it told me a code 44, defective map/02 sensor, low fuel pressure or malfunctioning injector. Could any one of these problems cause the car to bog down at a certain speed? Its almost as if spark or fuel is cut off when its bogging.. incredibly weird ****!

plz help!

[3.4 slow to go]

when was the last time the fuel filter was changed?

[V8 Killer]

few months

[3.4 slow to go]

ok, now that that's out of the way, we can proceed:

MAP can be checked for free using 2 ways: pencil way & free check way.

Pencil way: when the car is ideling, take a pencil, using the eraser end, tap the MAP sensor & see if it stumbles. If it does, it's bad & replace it.

Free check way: take the MAP into AZ/other parts store & have them test it in front of you. It should involve a vacuum gun & DVM.


step by step process of illimination going off the code. If MAP is good, then time to look at the o2 sensor, like $10/$15, and then the injectors (also check your vacuum line to teh fpr, but then it should bog down @ other spds too due to vacuum)

[V8 Killer]

Where exactly is the MAP sensor?

If the cars idle stumbles? or the actual sensor?

[ March 11, 2006, 02:15 PM: Message edited by: V8 Killer ]

[North Cali Autocrosser]

MAP sensor is on the passenger side at the rear of the engine bay, kind of hanging out in space above the evaporator. It's about 3in x 1in with a single vacuum line and a three wire plug.

[North Cali Autocrosser]

One thing I just remembered, my car had a simular problem and I thought the same couple of things. It turned out to be my fuel pump going out. Though I thought that the fuel pump would have just quit all together it slowly went out, making it hard to figure out til it finally just died. Just something to keep in mind.

[V8 Killer]

Thanks north Cali, Ill look in to that. So I tapped the eraser on the MAP sensor while the car was idling.. Nothing happened..

How much apx would a fuel pump job be?

[3.4 slow to go]

Originally posted by V8 Killer:

How much apx would a fuel pump job be?

first spend the $35 to get fuel pressure guage tester and find out if the pump is going

[blaine66]

Originally posted by 3.4 slow to go:
</font><blockquote>quote:</font><hr />Originally posted by V8 Killer:

How much apx would a fuel pump job be?

first spend the $35 to get fuel pressure guage tester and find out if the pump is going </font>[/QUOTE]My 97 Camaro with 3800 Series II is doing the samething. I had it serviced with fuel filter, plugs, wires, O2 Sensors(4), and it was still faulting. I replaced the 1/6 coil and the ignition plate and still loses power at 3-4K, revs up and drops...Did you figure your problem yet?

[Nikos95]

Yes indeed, check fuel filter, test map sensor, and pump. If all that checks out ohm your injectors, if thats good, run some good cleaner through them Chevron is the one I use, but after 1 bottle I change the filter again, cause it literally melts the element. If all the above doesn't fix it, you might want to get it checked for a vac leak. Still doesn't work, might want a compression check to find out if you have a bad gasket or rings.

Easy way to tell if you are running really rich or lean, look at your plugs.. I had a very similar problem in my Thunderbird, needed an injector, and my fuel filter was shot. Shortly after head gasket blew sky high..