Here are the specs first: 1987 Mustang, bone stock 302 speed density, AOD w/ 2.73 gears.... yes its 2.73, haven't put in the 3.73's yet. Car was originally a T5 car, the pedal is even still there. I assume it has the automatic speed density computer still since nothing except the tranny was changed over.



Problem: At night, first thing in the morning, or when it is cool outside the car runs like a demon, I can light up the tires even with the 2.73's out back. During the day when its hot as balls outside the car runs like ass, and when I say ass I mean fat sloppy ass. It stumbles at take off and while cruising down the road it runs like shit, it does not matter if I have the ac on or not. I have checked everything, the spark plugs, the timing, replaced my wires and coil, even got a MSD cap and rotor. I am stumped..... is my speed density going to shit? Would an incorrectly adjusted TV cable for my AOD cause this? Any help is welcome guys.... feel free to put your 2 cents in.

 

Sounds like a MAP sensor. Not sure without driving/testing the car myself. And btw there is no "speed density" part to go bad. Did this problem just start or has it always been like this? If you can't get it figured out you can always move north where its colder out

 

Where is the MAP sensor located? I was about to replace the TPS sensor

 

if u havent replaced the o2 sensors do it now

....when the car is cold it is not sampling from them and runs on a predetermined program fuel/ timing curve.

when it is hot it is gathering info from them and if they are old ....they give bad info, resulting in poor performance.

i also have an 87 notch, and it is good......

 

The MAP is on the firewall next to the brake booster. I doubt its the O2's just becouse exhaust gases are just as hot no matter if its 10 deg. bellow or 100 deg outside, but a bad O2 will cause that prob but all the time.

 

Oh really now. <Dave Chapelle voice> "Welcome to oxygen sensors 101, bitches. Everybody sit down, shut up, open your books and turn to Introduction to Oxygen Sensors." Read.

 

If that Mustang has a lot of miles and the oxygen sensors were never changed then change them. When you buy a used car expect to change a lot of things if not just one single thing. Old sensors working along with other older sensors through the car wreak havoc on the car's operation.

Clean or replace the idle air control sensor, make sure TPS is withing the .80 to .95 range, replace oxygen sensors, replace the coolant temperature sensor which sends the signal to the EEC (located on coolant return tube on right side of lower intake), get some CRC electrical contact cleaner and clean the "salt & pepper" connectors that are attached to the back of the upper intake running to the injectors (remember to use fresh electrical contact lube when reconnecting), and if the car has it's original TFI module these things can make the car run like a cinder block when they become hot/overheated. The MAP sensor is not that close to the brake booster. It's the black popsicle-shaped thing bolted almost center of the firewall above the upper intake and has a hose connected to it. When those get old they make the car run crumby, too. Gotta remember all these work in conjunction with one another and having a mixed bunch of old with new sensor is going to make the car run eractically.

 

Jebus..... I hate Fuel Injection........ thanks for the info guys. I will start with the O2 sensors, I know those have NEVER been changed out.

 

You can fix the problem or throw every sensor under the hood at it like HELMUT RONER wants you to do, but he must like over charging his customers or has been seriously ripped off in the past. And remember what I said at first ( with out driving/testing the car myself its hard to say) you can have any number of things wrong ( including an O2 sensor ).