I have a 1984 Pontiac Firebird. My mileage is slightly over 400k, I'm not sure on the exact amount because my odometer is wrong. I have had small issues with the car since I bought it, but nothing major. I am now running into several issues that are making it troublesome to drive.
My check engine light will come on and go off when I am driving for a long period of time. I caught it on and checked the error code and it was the MAP sensor. I have not done anything about that part yet.
My car will stall, and even die, when I slow down, unless it has been started for about 30 minutes. My heater is also only running mildly warm. I am thinking that these two are related and that my engine isn't heating up fast or well enough. I plan to flush the radiator and get a new thermostat. Also, if I floor the gas pedal it feels like it is going to die, but then catches and takes off.
The gas mileage has recently taken a dive. I used to get around 28mpg on the highway and now I am getting only about 15mpg.
I cleaned the carburetor and replaced the spark plugs and wires. I noticed some slight improvements, maybe it was just in my head, to the stalling when I floored the gas pedal, but it soon returned to it's prior behavior.

Does anyone here have any suggestions as to what might help alleviate some of these issues?

 

Welcome aboard thirdgen.org.

For the record, you can read the codes from the computer even if the light isn't on. It stores fault codes for 50 starts (unless the computer has had the power disconnected, like disconnecting the battery - that will clear the stored codes).

The keys to getting these cars to run right are to have everything working properly, and all adjustments set correctly - sounds simple, but seems to be overlooked regularly. If your MAP sensor is faulty, the poor engine won't be able to run correctly until it is working properly. So, find out why the computer thinks the MAP sensor is faulty (isn't always the sensor itself - by the way, exactly what trouble code was being set?).

If the thermostat is stuck open, the heater won't warm up. And, it's possible the computer won't go into closed loop - not likely, since it only needs to see 110 degrees, but possible. Wide open throttle is more of an open loop operation, though, so that issue may not be related to either the MAP sensor or not getting warmed up.

The two things that I've seen causing a bog when going WOT are timing improperly set, and the choke vacuum pull-off not working properly. Gets back to my first statement - make sure all of the components are working properly, and all adjustments set correctly. The timing needs to be set with the flat 4-wire connector from the base of the distributor to the harness on the firewall disconnected. You need a timing light to do this properly. The choke pull-off can be checked by pulling a vacuum on it and closing off the vacuum source - if the pull-off slowly releases (or doesn't pull in at all with vacuum), then the diaphragm is leaking and allowing the secondary air valve to open too quickly. The result is a bog when going from low RPM to WOT.

A less likely cause of the bog is low tension on the air valve spring. This is adjustable, but rarely goes out of adjustment (improving on the factory adjustment is another topic). The tension adjustment lock screw could have loosened or have been left loose, or the spring could have broken, but neither is particularly likely.

 

I'm not sure about the exact code at the moment. My book got damaged, so I don't know them anymore. Thanks for all the help, but there is so much stuff that I'm not sure where to start. Any suggestions?
Also, on another less dire note, my right blinker will not blink by itself. I have to move it on and off myself. I assumed this was due to the "blinker cube", not sure what the official name is. I can find the one, I assume for the left, but I don't even see a spot for the right one to go. The left one is a slight bit to the right of the steering column after I take the dash panels off. It clicks away when the turn signal is set to left, but it doesn't do anything when it's set right.

 

as for the blinker that happens to let you know there is a bulb out some where find it and replace it . should be fixed . replace mass air flow sensor . my OPINION. i had them go bad and did the same as your car replaced and fine . cant promise though.

 

I ran through and checked them when I first got it and that's what got the left one to work. Would the right one be independent? I was planning on replacing the sensor. I'm glad to see you had success doing that.

 

yes the rt is independant to help you figure what side is out dont know if its front or rear . some bulbs are multifunctional so if you turn on headlights and see all lights on dont just assume the bulbs are good. the portion of the bulb for tail lights may be fine while the directional portion may be fried .

 

I got it to work. It was a tough one. The front side blnker was out, but when I replaced it nothing happened, but if I shorted the bulb terminals it worked, but blinked faster than it should. I checked the bulbs in the back and there was one that wasn't getting a good connection. Part of the metal connector on the bulb was corroded and is eroded. I scraped it with a knife a few times and reseated it and after a couple of attempts it worked. I took the front side bulb out again and it still works. I was using the bulb I had just bought for my gear shifter.

While doing this I noticed that the car makes a clicking sound for a couple of minutes when I just turn the accessories on. It sounds like I am trying to start the car with a dead battery, but I can start it with no problems.

I've noticed this sound when I had a spark plug wire loose before, so I checked them all and they seem fine. Could it still be an issue with the spark plugs? I changed the plugs and wires on Christmas.

 

start the car in the dark and look for spark running around the base of the dist cap ,or any where else for that matter if there is spark at the cap replace it. good job on the blinkers!!!!

 

I tried and didn't see any sparks anywhere. Just to be sure you noticed, it happens before I even turn the engine over. I tried to replace my thermostat today, but I can't get the housing off. The bolts are stuck. I tried some rust remove and still a no go. After a 15 mile drive the coolant is still quite cold. I opened the radiator and accidentally got some on my hand, but it was ice cold. I didn't let it cool down at all because I was fairly certain, by touching the hose and guessing, that it would be cold.

 

Sounds like probably the mixture control solenoid in the carb. If so, completely normal and correct. Has been doing just like that since the day it rolled out of the factory.

 

Thanks, I've never noticed it before.

 

Good news everybody, all of the problems have been solved. I haven't had time to test the mileage, but I would it assume it went up as well. I borrowed some tools and was able to get the thermostat housing loose. To my surprise, there was no thermostat at all in there. I installed the one I bought. I also discovered that the temperature gauge works, but obviously, the engine has been running under 100F the entire time. After installing the thermostat it now sits around 200F.

Much to my dismay, the blower motor isn't working now. I will have to mess with it some more. I had it wired in directly just a couple of weeks ago because the switch was messed up. After some contact cleaning and a new fuse the interior switch started working, but seems to have found a different problem. The fuse is not blown this time, so I will have to try hooking it straight up and see what I'm up against.

Should I use radiator flush and clean out my cooling system? The fluid in the radiator is mainly green, with some slight rusty looking flakes floating in it. The reservoir is brown and gooey. According to a tester the fluid in the radiator is good to -10F I believe. I was planning on flushing it, but I have heard of stuff getting loose and then clogging the system. Should I just drain it a couple of times instead?

 

You should drain, flush, and refill the cooling system. If there is stuff floating in there, the anti-corrosion capability of the antifreeze is depleted.

A "reverse flush" is the best option, as it runs the flow in the opposite direction of the normal coolant flow, which tends to loosen stuff up better. But, it usually isn't necessary. The best cleaning do-it-yourself flushes, in my opinion, are the ones that require draining the antifreeze before adding, and take about half an hour of running to do the job. The best way to do the do-it-yourself flush after the cleaning is to get a flush kit that goes in the heater hose and runs the opposite direction of "normal" coolant flow and gets it out of the system through the radiator cap.

It isn't unusual for this operation, whether done by a shop or by yourself, to cause the water pump to start leaking. For that reason, it's typically recommended to do the flush before changing the water pump, if that is in your plans. So, don't be surprised if the water pump starts leaking afterwards, even if you didn't plan on replacing it before you did the flush.

Clean out the reservoir while you're doing the flush. Also not a bad idea to change the radiator cap, and all coolant/heater hoses.

 

I was told by another person on a different forum to not flush yet. I was told to drain it and put in 100% antifreeze with no water and run it until spring. I was told that would help lubricate the water pump bearings and coat the water jackets with anti-rust compounds.

I was planning on using this http://www.walmart.com/ip/Prestone-F...l-Kit/16817507 & this http://www.walmart.com/ip/Prestone-S...-22oz/16817504

Also, How do I get the reservoir off? It is attached by a plastic screw looking thing.

Looking at water pumps, I can get an aluminum pump for only $3 more. Would that be a wise choice? It comes with a Limited Lifetime Warranty, while the standard pump only has a year warranty.

 

Sorry for the poor advice you received elsewhere.

Drain the current coolant, flush out with water. Then add a flush/cleaning agent per the directions provided with the product. Reflush, add antifreeze to obtain a 50/50 to 70/30 mix of antifreeze to water.

To remove the overflow reservoir, unscrew the center screw, and pull the whole fastener off. All the screw does is expand the fastener flutes on the back side of the fenderwell.

The aluminum water pump should be fine. A couple of pounds lighter than a cast iron pump, not enough to be able to notice any difference. A better warranty should be worth the extra $3.

 

I noticed something else, when I drove a good distance on the interstate, when I am in overdrive and open the throttle it will stall and the RPM will drop. It seems to happen when the gears shift. It only happens around 60+ MPH and it doesn't happen when I am in drive,