My 1987 Ranger has had this intermittent problem for about a month now. Fuel pressure & ignition system is normal. It was coughing in the mornings when cold, but I corrected this by changing the Air Bypass Valve. I also found the EGR Valve not opening, so I replaced it along the the EGR Solenoid, still no help! I also checked all vacuum lines, no leaks noted! I'm wondering if I have some clogged injectors? But if so, why is my problem intermittent? Wouldn't it be running rough at all times if the injectors were clogged? I'm getting tired of throwing parts at it, I could use some good advice! Thanks, Elwood

O.K. How about this one? When this all started, my only fault was a TPS fault. So, I changed the TPS, & no help! What I'm thinking about is? Maybe the Mass Airflow Valve, caused the TPS fault? After all, I do have 285,000-mi. on my pride & joy. Ha! I would greatly appreciate any inputs! Adios! Elwood

After checking or changing nearly everything that could be related to this problem, by the way, it surges most of the time when the engine is at normal operating temps. Not when it's cold! Does anyone know if it could be a plug exhaust converter, or bad fuel injectors?

After a month & a half of T/S, and close to $400 of throwing parts at it, what ended-up being the fix was an EGR sensor! The things that were actually wrong with my 2.9L were: a couple of leaking vacuum hoses, a cracked power brake check valve, air bypass valve, & the EGR sensor.