[TheRange]

I have a 91 classic with the 3.9 and a couple days ago i got in it and realized that when i push down the throttle nothing happens. The engine doesnt rev up to higher rpms and when i hold it to the floor it loses more power and sounds like its going to stall. Its not even going higher that 15 mph down the road and 5 uphill. I've replaced the fuel filter, checked for kinked fuel lines, replaced and cleaned vacuum lines and still its doing the same thing. three months ago ive replaced the plugs, wires, exhaust maifold gaskets and done a regular tune up so i dont know what it could possibly be. I sounds like the engine is clogged and is not getting any fuel so im not sure if its the TPS or the fuel regulator. Has anyone had this problem and got it going again?

 

[TheRange]

I looked at the Diagnosic Box under the passager seat and it came up as a code 44 (left oxygen sensor). Could this sensor be causing me not to have any throttle?

 

[Albrein]

No, oxygen sensor problem is not enough reason for no throttle at all. ECU changes to limp mode when the sensors are not working properly, but you the engine still runs.

Have you checked the fuel injectors?

 

[rufant]

So did this just 'happen'? What were you doing at the time? Working on the car? Driving along the road? Starting car in the morning? Washing the engine?

Have you checked the the inlet tract is clear (take off the inlet piping) and the throttle assembly work correctly? Also does a normal amount of gas come out of the exhuast when the engine does run? No hissing or pressure building up noises from the exhaust?

Can you check the ignition timing with a timing light, same with fuel pressure?

Check all engine related electrical connections and wiring for problems.

Do you know how to check cam timing?

 

[TheRange]

i was driving the car when i noticed it happened and then it was gradually getting worse. the exhaust sounds like nothings getting backed up and im going to be the one working on it but i dont have a timing light or a fuel pressure tester on hand to see if its either missing out or not getting the right amount of fuel. It would idle fine when you start it up but if you give it gas it boggs down to were it almost sounds like it wants to die. ive checked the throttle assembly and it looks like its working fine but i dont want to throw parts at it if the parts arent gonna fix it.

 

[rufant]

Ok, the list of things that could cause this is very long. Without certain pieces of diagnostic equipment you are going to struggle to accurately diagnose the problem. Therefore you are looking at a 'swaptronics' approach of putting best guess parts on the car to see if they cure the problem. Which you have said you (rightly) don't want to do. I'm afraid it's impossible to say those symptoms means it's a XYZ or whatever.

I would probably recommend booking it in with a decent recommended workshop to fix, as they will have the knowhow and the facilites to make an accurate diagnosis.