Newbie - 92 Bronco is Sluggish

Hey everyone! I just picked up a 92 Bronco XLT with a 5.0 with around 212K on the motor. The thing starts up, and idles smooth as silk. I checked compression, and pulled codes, and had it smoged. All seems well with the engine. It runs well once I get it up to cruising speeds. However, dead stop, and at times mid-range acceleration seems very sluggish. Now keep in mind the last ford (Mustang LX) I drove had a H.O 5.0 in it and that was many years ago, but the acceleration was much better, gas peddle was more responsive, and the mustang felt torquier than this Bronco. So the $1K question is what's up?  Is this all I should expect from a 24 y/o Bronco? There are times that I can mash on the peddle at lower speeds and the tranny kicks down and I can get up and go. From a dead stop... not so much until around 3.500 RPM. There are other times when I mash the peddle and... trickle. no kick down, no get up and go. This happens at warm and cold engine temps. This may be unrelated, but I'll mention it anyway. It seems smelly, like fuel and exhaust. The down and up shifting of the A4OD seems jerky and a little unpredictable at times.

Okay so all that said: I haven't wrenched since I was a younger man, so my confidence has waned over the years. I'll be taking it in for a full work up at my local mechanics shop, but I'm curious if there's something in particular with 90's Broncos that I should be aware of. Vacuum issues, running too rich, timing out of whack, throttle body linkage? ECU? Any thoughts or advice are welcome.

I apologize if this has been covered before, I looked around and found a few similar but not exact threads. Thanks in advance folks!

Yo ih8gamerz,

Welcome!

No worry, I have realized in past year that I am now beyond crawling under the Bronco and spending hours there

So, no codes, right?

If any we can do some pin point tests on usual suspects such as;

throttle position sensor (TPS,

transmission range (TR) sensor aka Manual Lever Position/Transmission Range (MLPS/TR) Sensor, etc.

If none:

Air conditioning Vacuum Leak Diagnosis;

a leak in the vacuum control circuit will send all airflow to the defroster outlets. This condition may occur during acceleration (small leak), may exist at all times (large leak) and may happen only when certain specific functions are selected, indicating a leak in that portion of the circuit.

Does this occur now?

Anyway see my vacuum leak diagnosis in my post #20 at

http://broncozone.com/topic/23994-90-58l-getting-continuous-code-33-and-running-code-44/?p=125535

Best to use a vacuum gauge, connect it to the tee on driver side of intake manifold.

Is the Transmission Control Switch (TCS) and Indicator Lamp (aka overdrive on/off switch and led) blinking while driving?

I have a 96 but no tach, it does not have much kick down (forced downshift)at higher rpm's. Ford has a procedure for "Poor Vehicle Performance" without a code as well as other E4OD issues:

Possible Component Reference/Action

253 — ELECTRICAL ROUTINE

Powertrain Control System

Perform torque converter operation test.

Electrical inputs/outputs, vehicle wiring harnesses, powertrain control module, other engine related items, torque converter clutch solenoid, throttle position sensor, transmission range (TR) sensor, transmission fluid temperature sensor

Run On-Board Diagnostics. This is the code test. Refer to Powertrain Control/Emissions Diagnosis Manual for diagnosis. Perform Service Manual Pinpoint Tests B, C and D using Rotunda Transmission Tester 007-00085, Cable and Overlay 007-00107 and the Transmission Range (TR) Sensor Cable "B" (MLPS Manual Lever Position Sensor Tester Cable) 007-00086 or equivalent as outlined in this section. Service as required. Clear codes, road test and rerun On-Board Diagnostics.

353 — HYDRAULIC/MECHANICAL ROUTINE

Shift Linkage (Internal/External) or Cable

Damaged, misadjusted

Inspect for damage. Service as required. Verify linkage adjustment as outlined. After servicing linkage, verify that the transmission range (TR) sensor is properly adjusted. Refer to In-Vehicle Service in this section.

Shift Scheduling

Perform Shift Point Road Test procedure as outlined in this section.

Improper

Go to the appropriate diagnostic routines for shift concerns

No. 210-211.

Engagements

Improper gear selection

Go to the appropriate diagnostic routines for shift concerns

No. 215/315.

Converter Clutch Always Applied

Go to routine No. 341.

Converter One-Way Clutch

Damaged

Go to Torque Converter Checks in this section.

This is from Section 07-01A: Transmission, Automatic, E4OD

DIAGNOSIS AND TESTING

Diagnosis by Symptom @ http://www.diesel-dave.com/vehic/manual/stj/stj71a24.htm#extract_1037

Look at the other issues, they may ring a bell.

In,

96 Bronco-F-Series Workshop Manual (PARTIAL) by FORD via

http://www.diesel-dave.com/vehic/manual/stj/stjleft.htm

Same as most earlier years especially 92-96, except for: OBD II in 96; 4WABS (93-96); RABS (87-92); Air Bag (94-96); 3 ***** Automatic Locking Hubs (Built from May 95 through 96); Spark Plug Wire Routing & Firing Order (The firing order for 1987-1993 5.0Ls is 1-5-4-2-6-3-7-8. The firing order for 1994- 96 5.0Ls & all 5.8Ls is 1-3-7-2-6-5-4-8.); R134a in 94-96;

2-piece Spindle Rolling Diaphragm Seal (RDS) used on 5/95 to 96 Broncos & F Series 1/2-ton 4WD;

and a few other items that I still need to research such as Mass Air Flow in 95 5.8 California models and in all 96s, other years used Manifold Absolute Pressure Sensor (MAP).

Thanks for the reply and all the info! I am taking her in to have the fuel, exhaust, vacuum, and transmission looked at. I've noticed now that the truck is MUCH more responsive when the A/C is off and I have disengaged the O/D on the transmission. I checked plugs, wires, and firing order. All is well there. I'll see what the pros have to say for the truck.

In the meantime, I've purchased a 347 stroker short block from Coast High Performance, and will be purchasing Edelbrock Performer heads, Performer upper and lower truck intake, and am currently looking for a good cam to ram in there. I should get close to 400 HP on the engine when all said and done. The block and the heads are 50 State Legal and the intake should pass Nevada smog with an EGR in place. I'm focused on maximizing HP/torque from idle to around 5500 RPM, which will make her a better on-road driver, and when mixed with lower gears will make a competent weekend off-roader. I'm very excited, but not in a hurry. I'll post picks once the parts arrive.

Consider upgrading the drive train components, ie. U-joints, drive shaft, axles, differential.  The stock components have a tendency to snap under high torque.

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