I have a 1990 Blazer that I can’t seem to figure out what’s wrong with it…I have replaced the fuel pump, fuel filter, ran a new exhaust, drained the gas out of the gas tank, full tune up,…but it still hops and skips when trying to maintain a steady speed and after draining the gas it caused it to run worse than before…I can’t figure out anything else I can do…Is it a fuel problem or an electrical problem? Please help! I have had this truck 6 months now and can’t get it to run right…
Possible fuel pump relay is faulty,
Loose/dirty or corroded electrical supply wire to pump,
perhaps the fault isn’t with the fuel system, but is an ignition system one?
Any codes stored? OBD1?
Check the entire secondary ignition system. What type and brand plugs are installed?
What about Ford’s infamous TFI ignition module which (often) is attached to the side of the distributor with two screws? Either Haynes, or Chilton’s, repair manual should have a through testing section on the primary, and secondary, ignition system. Tried it?
Thanks guys for taking the time to reply, after all the money and all the checking everything you’ve mentioned, along with other stuff…it was the alternator causing the problems. The voltage regulator was burned up and the alternator was putting out 16v and as a result was shutting down the fuel pump, ECM, etc…so it’s running like a champ now. So thanks again guys!
This vehicle doesn’t have the Ford TFI module… it’s a Chevy.