1989 Class-C 25-foot Ford E350 RV gasser with 79K miles (first-year fuel injection).
Question: Upon start-up while preparing for a trip in Feb. 2022 there was a loud noise like something broke, clattered, and/or something in the bottom end.
Upon subsequent start-ups, it does not repeat the noise, but now what I get is after revving up the motor, as it settles to idle, there is a rattling (almost like a baby noise of the initial noise), seems like noise is from the bottom end except I cannot pinpoint where. it is when I rev the motor in neutral that it settles. And other than the rattle that settles, it seems โnormalโ. As far as the behavior when driving, it slowly, gradually loses power until Iโm creeping along in the shoulder, then the tow truck. My thinking tells me if it was a catastrophic failure in the engine, as was my first thought, then it wouldnโt run at all. My home made other demands on my time this weekend (can you say garbage disposal?), so I have not gotten under the rig yet.
In the Fall of 2021 the RV would not pass smog. The goal was to get the vehicle to pass smog, which it did, but it was also in need of a tune-up. Some work done by the shop, some I did myself. Took one trip after tune-up with good performance, but now this problem. I am able to back the vehicle out of the driveway and drive (slowly) on my residential street and put it back in the driveway, but I cannot get on the highway. A mechanic friend suggests it might be either the heat riser (does the FI engine even still have a heat riser??), or the Cat, but neither of those make sense to me. Please advise. TY.
Work done to this point.
Tune-up (fluids, sparks, wires, distributor cap, rotor, belts, hoses)
Map sensor checks ok
Battery ok
PCV valve ok
Fuel pressure regulator replaced
Catalytic converter checked out ok
O2 sensor replaced
Fuel filter replaced
Fan clutch replaced (3 years ago)
Fuel pump replaced (Twice!!)
