1986 Mustang gt cant hit rpms or go half throttle

Mustangman_1969 · 09-30-2009

hey, my 86 gt wont hit rpms at all.. if i give it bout half throttle it will only hit bout 2500-2700 than start aputtering out...if i give it more than half throttle it happens earlier..
when im already at 2500-3000 and i put it to the floor the motor sputters than cuts out completely till i let off and it starts running again..

thought it was wires so i bought brand new taylor wires and a pro billet distributor and it still happened...i have some vacuum leaks but ive had them long before it started do this
i really dont wanna spend a lot of money buying tons of parts that wont help me
please help

hotshot · 09-30-2009

have you tried the basics like cleaning your TB and intake? If you are Fuel Injected be sure to check your MAF as well. Perhaps there is indeed a leak, try having someone (who is brave) stand near the open hood while you step on the gas to see if they can pinpoint a location of the leak or at least give you more info.

Mustangman_1969 · 10-08-2009

its an 86 so no maf..do you really think its something simple like that...

302Feen · 10-08-2009

If you have a vacuum leak, it needs to be fixed. That could be at least one of the problems.

Mustangman_1969 · 10-08-2009

ya i will fix them..but i had them when i bought the car and it ran way better than then it does now..

302Feen · 10-08-2009

I don't know a lot about the '86s but do you have a Throttle Position Sensor (TPS)?
If so, you might check and be sure that it is at the right voltage.

302Feen · 10-08-2009

Also, delayed timing can cause that "sputtering" you are talking about... Have you checked your timing?

**EagleAutosports** · 10-08-2009

This sounds like a problem in the timing/ignition system. When it won't rev, that's usually the problem.

If you've replaced the wires, I have to ask a dumb question but are they on correctly? That's not being a smart ass, I've seen many mix up the #5 and #6 plug wires and have this happen.

Are the harness connectors in good shape? I've had a wire come loose inside the connector and cause problems but it looked fine from the outside.

Are the plug wires snapped onto the plugs, I've seen the connector inside the boot go to the side rather than on the plug and cause an errant spark.

Mustangman_1969 · 10-18-2009

hey i checked all wires and they are good..right where they are suppose to be and all have good connection... idk what to do next...think my coil could be shorting out on the inside..or just bad

Mustangman_1969 · 10-21-2009

anyone? anything is option is excepted

Mustangman_1969 · 10-23-2009

hey a have a friend who said that it may be something wrong with the heads or the head gaskets

Mustangman_1969 · 2 Weeks Ago

i tested my compression and it was good and today i tested my fuel pressure and it was low...they look for 30-45 and prefer closer to 40-45 and i was sitting at 29 psi. my fuel pump and filter are both new.. and i was told the regulator could be causing my lack of fuel and burn too lean hence the loss of rpms