newbe in need of help. i am the org owner of this veh close to 400 tho. within the last three days the truck is running like it wants to be turned into a tuna can. i have replaced the fuel pump, filter, vac lines, iac, tps, fuel reg, map and ign mod and temp sen. cats appear clear. idol somewhat smooth to rough although it has a noticed drop in rpms. sometimes to the extent that it wants to stall. taking off if i dont peg it it will miss and bog down. back off the gas sometimes it levels out. rpms besides felt and noticed the tach is bouncing all over playing **** with shifting. no codes unless i unplug a sensor. not backfiring but that dosent mean the chain didnt stretch after the milage or could it be the computer
bucking bronc 351w
- Thread starter watashie
- Start date
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yo W,
WELCOME!
I assume it is a 95?
If so;
You can try going through
FORD's 1994 PCED OBDI-A
SECTION 2A: Diagnostic Routines
http://www.thedieselstop.com/faq/9497faq/maint/vra/vra02005.htm
But only basic checks are shown bwc most of this doc is partial
for example;
Hesitation/Stumble - Acceleration - 9
http://www.thedieselstop.com/faq/9497faq/maint/vra/vra02014.htm#vra02chart9
PRELIM. CHECKS
VACUUM (LEAKS, ETC.)
AIR FILTER
FUEL QUALITY
ELECTR. CONNECTORS
IGN WIRING
and No Codes unless.... did you check for both KOEO (Key On, Engine Off) & KOER (Key On, Engine Running?
Vehicle Emission Control Information (VECI) Decal; Contains Vacuum Diagram & Calibration Parts List for 88 & UP. On-Line for Free at Ford. Click "Quick Guides" in left panel; Scroll to & CLICK VECI Labels "Provides Vehicle Emission Control Information (VECI) and a related calibration parts list." Enter applicable info (need to know your Calibration number from your B-pillar sticker). Vacuum Diagram is the same as the one on the core support or hood or air filter cover. Suggest Right Clicking this Hot Link & Open in New Window
Source: by Ford at motorcraftservice.com
"...The vacuum gauge should show 18-22 in-Hg @ idle, and maintain a steady needle. Rev it up to ~2500 rpm, hold it steady, and you should see the needle drop, then slowly increase to a level close to the idle reading (though slightly lower is normal)..."
Source: by SigEpBlue
Vacuum Leak Test; On an idling engine check for vacuum leaks using a mechanic's stethoscope with the probe removed, or a ~3' garden hose section. Don't spray flammables on a running engine. MIESK5 NOTE; Also check: vacuum hoses; intake manifold gasket & throttle body; PCV line; vacuum reservoirs: EGR Sys Vacuum Tank & 2ndry air (coffee can); AC, heater, defroster, vent control ckt & vacuum tank (plastic ball type), under dash & lines to heat/blend/etc. doors; power brake booster; cruise control ckt, etc.... where applicable; ( BEWARE OF BELTS/PULLEYS, FAN AND HOT ENGINE
Source: by SEABRONC & miesk5 at http://broncozone.com/topic/23994-90-58l-getting-continuous-code-33-and-running-code-44/
see post #20
Vacuum Leaks, Finding; "...Cracked or broken vacuum lines, leaking intake manifold or plenum gaskets, injector o-rings, broken emissions solenoids, open vacuum ports are just a few of the causes of vacuum leaks. Use the under-hood emissions diagram and check every single vacuum circuit with a vacuum tester such as the Mityvac tool. A faster technique for finding intake manifold vacuum leaks is to get a bottle of propane and attach a length of rubber hose to the gas valve. Start the engine, be careful not to come too close to the fan or fan belts. Open the propane tank valve so you have a steady flow of gas. Then hold the hose near suspected leak points while the engine is idling. If there is a leak, the propane will be drawn in through the leak. The propane should cause a noticeable change in idle speed and/or smoothness. Always know where the closest fire extinguisher is and how to use it!..."
Source: by Ryan M (Fireguy50)
Also, fyi;
95 Bronco-F-Series Workshop Manual by Ford
https://www.motorcraftservice.com/pubs/content/~WSSJ/~MUS~LEN/20/SSJMAIN.HTM
WELCOME!
I assume it is a 95?
If so;
You can try going through
FORD's 1994 PCED OBDI-A
SECTION 2A: Diagnostic Routines
http://www.thedieselstop.com/faq/9497faq/maint/vra/vra02005.htm
But only basic checks are shown bwc most of this doc is partial
for example;
Hesitation/Stumble - Acceleration - 9
http://www.thedieselstop.com/faq/9497faq/maint/vra/vra02014.htm#vra02chart9
PRELIM. CHECKS
VACUUM (LEAKS, ETC.)
AIR FILTER
FUEL QUALITY
ELECTR. CONNECTORS
IGN WIRING
and No Codes unless.... did you check for both KOEO (Key On, Engine Off) & KOER (Key On, Engine Running?
Vehicle Emission Control Information (VECI) Decal; Contains Vacuum Diagram & Calibration Parts List for 88 & UP. On-Line for Free at Ford. Click "Quick Guides" in left panel; Scroll to & CLICK VECI Labels "Provides Vehicle Emission Control Information (VECI) and a related calibration parts list." Enter applicable info (need to know your Calibration number from your B-pillar sticker). Vacuum Diagram is the same as the one on the core support or hood or air filter cover. Suggest Right Clicking this Hot Link & Open in New Window
Source: by Ford at motorcraftservice.com
"...The vacuum gauge should show 18-22 in-Hg @ idle, and maintain a steady needle. Rev it up to ~2500 rpm, hold it steady, and you should see the needle drop, then slowly increase to a level close to the idle reading (though slightly lower is normal)..."
Source: by SigEpBlue
Vacuum Leak Test; On an idling engine check for vacuum leaks using a mechanic's stethoscope with the probe removed, or a ~3' garden hose section. Don't spray flammables on a running engine. MIESK5 NOTE; Also check: vacuum hoses; intake manifold gasket & throttle body; PCV line; vacuum reservoirs: EGR Sys Vacuum Tank & 2ndry air (coffee can); AC, heater, defroster, vent control ckt & vacuum tank (plastic ball type), under dash & lines to heat/blend/etc. doors; power brake booster; cruise control ckt, etc.... where applicable; ( BEWARE OF BELTS/PULLEYS, FAN AND HOT ENGINE
Source: by SEABRONC & miesk5 at http://broncozone.com/topic/23994-90-58l-getting-continuous-code-33-and-running-code-44/
see post #20
Vacuum Leaks, Finding; "...Cracked or broken vacuum lines, leaking intake manifold or plenum gaskets, injector o-rings, broken emissions solenoids, open vacuum ports are just a few of the causes of vacuum leaks. Use the under-hood emissions diagram and check every single vacuum circuit with a vacuum tester such as the Mityvac tool. A faster technique for finding intake manifold vacuum leaks is to get a bottle of propane and attach a length of rubber hose to the gas valve. Start the engine, be careful not to come too close to the fan or fan belts. Open the propane tank valve so you have a steady flow of gas. Then hold the hose near suspected leak points while the engine is idling. If there is a leak, the propane will be drawn in through the leak. The propane should cause a noticeable change in idle speed and/or smoothness. Always know where the closest fire extinguisher is and how to use it!..."
Source: by Ryan M (Fireguy50)
Also, fyi;
95 Bronco-F-Series Workshop Manual by Ford
https://www.motorcraftservice.com/pubs/content/~WSSJ/~MUS~LEN/20/SSJMAIN.HTM
