Slow acceleration

[my98SVTturbo]

My 99 SVT was sitting for about 4 years and I finally just got it on the road. The issue I am having is with very sluggish acceleration. The car is very slow off the line and it doesn’t matter what gear I am in it take forever to accelerate. The car also seems to rock back and forth a lot at slow speeds (thinking this is the motor mounts?). I was thinking it could either be a bad IMRC or clogged cats? I don’t have a CEL on though so I am not really sure what may be causing this. The car "runs" fine and there is no stuttering or a rough idle but its just during the acceleration. What do you guys think?

 

[gmorrell]

Old fuel maybe? Did you put fresh fuel in the tank?
Did you put any fuel stabilizer in the tank prior to storage?
Stored cars that have old fuel in the tank can often clog the fuel filter pretty quickly when they're run again. Checked the fuel pressure?
Battery OK? New battery after storage? Is the charging system charging the battery? After 4 years, the average car battery is junk whether disconnected or not.
A Battery Tender might have saved it, but even 4 years is a long time on a Battery Tender.
You can verify the IMRC function by looking at the linkage (under the throttle body) with a flashlight and opening the throttle so the engine revs solidly past 4,000.

Clogged cats is a bit of a stretch at this point, you have a lot of much simpler stuff to eliminate first.

Maybe after the F150 Lightning and the Focus ST3 you just forgot how slow the CSVT is? :laugh:

 

[my98SVTturbo]

Yeah I replaced so much stuff on the car with brand new parts.

Fuel pump assembly, alternator, battery, plugs, coil wires, coil pack, injector cleaning, full suspension, full brakes, burned all of the old fuel off and filled it up with 93. I was thinking that about the lightning and ST but my SVTF feels faster as well. Not sure, Will check the IMRC out.

 

[crewchiefpro]

Hook a vacuum gauge up to check for plugged cats after verifying the stuff gmorrel brought up. Low vacuum at idle and none at very low throttle can point to a plugged exhaust.

 

[amc49]

Still did not mention fuel filter and could easily be that............

 

[99contourSE]

I had the same problem with my 99 SE. I thought the throttle body needed cleaned and when I sprayed throttle body cleaner into the intake it ran fine for about five minutes. This made it seem very deceptive. Had me stumped for forever. Eventually I started checking plugs and plug wires. Turns out the plug wire to cylinder two was only sometimes working... Still doesn't make sense to me that the throttle body cleaner was helping it, but a new set of spark plug wires solved my problem.