slight hesitation

[pete315]

friend has a 95 MTX SHO. he's getting a slight hesitation (bucking) at low rpms while trying as you try and accelerate slowly, mainly in 2 and 3 gear. it does not happen all the time. there are no codes stored and no CEL. I changed the fuel filter, still same problem. any ideas? could a bad IAC cause this?

 

[CerberuS]

Whats the condition of the plugs , wires , crank sensor?

any oil in the plugs wells?

 

[pete315]

new plugs,wires,valve covers gaskets, 60 K done about 10,000 ago with new CPS. it's weird, when you step into it, car runs great. no bucking,hesitation. has great idle. it's just on slow accel at low RPM, he gets a slight bucking. and not all the time. I'm betting it's a dirty sensor, but which one????

 

[CerberuS]

some codes?

 

[pete315]

I went to pull codes with paper clip, no codes stores. heard fuel pump kick on, fans turned on, but has not codes.thats the problem.

 

[esahlin]

Worn or wearing pressure plate and clutch disc can cause this sometimes.....how many miles on the clutch and pressure plate?

 

[93rev2sev]

Mine does the same.

Does the computer know if the secondaries are operating properly?

 

[pete315]

30 K on clutch. I'm thinking maybe one of the fuel injectors is dirty.

 

[Howdy_Doody]

What kind of plugs did you use?

 

[pete315]

previuos owner use stock motorcraft

 

[Markus]

My 95 ATX had the same issue - bucking under gradual throttle changes. Josh at SHONUTPERFORMANCE suggested the MAF was shot. In my case he was right. I had no codes, either. IIRC Josh suggested, as a test, disconnecting the MAF temporarily to see if the bucking went away. I disconnected the bad MAF and the bucking went away. New MAF cured the problem.