'91 Hesitation under WOT

[9091SHOs]

Hey Guys,
I am in need of some help. I have a '91 that is having a strange issue, when driving along at lower RPM (no matter what gear) if I go WOT the car hesitates and stumbles. The strange part is that if the car is above 3,000 RPM and I go WOT it runs great, secondaries open up and it will scream the whole way to 6,000 RPM. The CEL never comes on. I cleaned the MAF as it was somewhat dirty and it made no difference. I found out today, that I can simulate it from under the hood using the throttle body. From idle, I can pull the throttle body and it will rev cleanly, while coming down from the higher RPM if it hit the throttle body again it will do the hesitation/stumbling. Any help will be greatly appreciated!

 

[zoomlater]

Pull your codes and report back

 

[9091SHOs]

Will there be codes if the CEL never comes on?

 

[zoomlater]

yes, better to check and know what the car is telling you is wrong before throwing parts at it

 

[9091SHOs]

Agreed, wasnt sure if codes would be present if the CEL never came on. I will report back with codes once I get them. Thanks

 

[9091SHOs]

Sure enough! The KOEO test provided code 63 which from what I am finding is the Throttle Position Sensor voltage too low.

 

[zoomlater]

That should be an easy fix, TPS sensor are relatively inexpensive. In fact, just bought few off ebay for $14 each

 

[Jbeck]

How dirty is the intake? Might be time to clean intake and IAB

 

[luigisho]

If you're shooting cleaner hit the MAF while you're at it.