having problems

[david692]

I have an 88 ford bronco with the 351. For the last few week I have been battling i issue with my truck sputtering both at idle and when driving.

being only seventeen i have not learned everything about how to work on cars and trucks just yet most of the issues ive had in the past i have been able to figure out myself but this one has me stumped. everything Ive tried has been a swing and a miss. so far i have tried fuel filter, distributer cap and rotor, spark-plugs, spark plug cables, pcv, and messing with the timing and i haven't yet got it solved. the truck seems to come close to stalling and the rpms drop Anyone have any ideas?

 

[miesk5]

Yo!

Welcome to da Zone David!!!

Suggest you begin with this basic check for vacuum leaks and Diagnostic Trouble Code DIY testing by my friend, BroncoJoe19

do the KOEO = Key On Engine Off portion first

& Remember to have engine @ Normal Operating Temperature before doing the KEY ON ENGINE RUNNING (KOER) portion

Post any Code(s) found here.

Also ck for vac leaks under dash for AC/Heat/alt control doors...

When you go thru a Yard for parts ot have the $ for it, get a Vacuum gauge; it will be one of best under $15.00 troubleshooting thAngs you'll ever get.

Some mount it on/under dash for use as a MPG indicator; (higher the better, meaning less pedal to da metal)



In-Dash pic in an 83 by Steve83

Vacuum Gauge Diagnosis - BEST!; Normal engine; Steady gauge 18"-20" at all speeds..." READ MUCH MORE Source: by Craig U at classictruckshop.com

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; (combined w/ Steve83's info, thnx) BEWARE OF BELTS/PULLEYS, FAN AND HOT ENGINE

Source: by miesk5 & Steve83 at Ford Bronco Zone Forums

for timing Adjustment in Ford EFI Engines; MIESK5 NOTE; Spark timing that is ******** from specification may increase exhaust gas temperature and shorten catalyst life. Refer to the following procedure for service details. a. Check spark timing. Check base timing with spout disconnected. Set base timing to the specification on the vehicle emission decal. b. Check computed timing with spout connected. NOTE: COMPUTED TIMING IS EQUAL TO BASE TIMING PLUS 20° BTDC ± 3°. Source: by Ryan M (Fireguy50) at fordfuelinjection.com

SPOUT Location pic @ distributor in an 88 Source: by Jem270 at SuperMotors.net