I have no or little pick-up first thing in the morning(cold) and as the day progresses it gets better...a little better. I dunno..clogged cat-converter? how is a back pressure test done? Or do I need a pyrometer?

Drop the exhaust.

Take your shop vac to the muffler end.

Make sure you've got a good seal, and check the

Y pipe inlets for good suction.

there's any number of things that could cause this.

 

what engine? carb? FI? MPFI? mileage? recent tune up? have you check for spark? how loud is the fuel pump? plugs, wires, cap, rotor, air filter, vacuum leaks, any check engine lights? any recent work, what was the last check engine light?

there's any number of things that could cause this.

 

what engine? carb? FI? MPFI? mileage? recent tune up? have you check for spark? how loud is the fuel pump? plugs, wires, cap, rotor, air filter, vacuum leaks, any check engine lights? any recent work, what was the last check engine light?

 

no cel. SPFI EA82, new plugs & wires, new cap and rotor, new air filter. 61,200 miles. I am stumped.